How can electronics on board JWST survive the low operating temperature while it's difficult to survive lunar nights?Can the James Webb Space Telescope basically manage its own orbit if necessary?How will JWST manage solar pressure effects to maintain attitude and station keep it's unstable orbit?Have any lunar probes used a cold shield?How can a sounding rocket accurately take the temperature of the atmosphere while flying through it at high speed?How can I find a daily record of the temperature on Mars?How much of the sky can the JWST see?How can the 6.5 m primary mirror of the JWST fit inside the 5.4 m fairing of Ariane 5?
Multi tool use
Why does one get the wrong value when printing counters together?
How can Paypal know my card is being used in another account?
Three Dots in Center Page
Applications of pure mathematics in operations research
Is it unprofessional to mention your cover letter and resume are best viewed in Chrome?
Exploiting the delay when a festival ticket is scanned
Correct word for a little toy that always stands up?
How would a lunar colony attack Earth?
What Marvel character has this 'W' symbol?
What is a good example for artistic ND filter applications?
Why tantalum for the Hayabusa bullets?
Did Vladimir Lenin have a cat?
What is my clock telling me to do?
Is it okay for me to decline a project on ethical grounds?
Can you continue the movement of a Bonus Action Dash granted by Expeditious Retreat if your Concentration is broken mid-move?
Why would an invisible personal shield be necessary?
Why don't short runways use ramps for takeoff?
How can I solve this sudoku?
Patio gate not at right angle to the house
How can I convert a linear narrative into a branching narrative?
Embedded C - Most elegant way to insert a delay
Typesetting numbers above, below, left, and right of a symbol
Move arrows along a contour
Antonym of "Megalomania"
How can electronics on board JWST survive the low operating temperature while it's difficult to survive lunar nights?
Can the James Webb Space Telescope basically manage its own orbit if necessary?How will JWST manage solar pressure effects to maintain attitude and station keep it's unstable orbit?Have any lunar probes used a cold shield?How can a sounding rocket accurately take the temperature of the atmosphere while flying through it at high speed?How can I find a daily record of the temperature on Mars?How much of the sky can the JWST see?How can the 6.5 m primary mirror of the JWST fit inside the 5.4 m fairing of Ariane 5?
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;
$begingroup$
Compared to the temperatures encountered in lunar nights, the desired operating temperature of the James Webb Space Telescope is very low. Lunar nights are typically -170°C while the operating temperature of JWST is -220°C.
If surviving the cold lunar nights is difficult for the electronics, say on lunar rovers, then how does JWST overcome this issue?
And why not make use of the same methods adopted in JWST onboard the lunar rovers to survive lunar nights, avoiding the notorious nuclear heating?
rovers temperature james-webb-telescope lunar-module
$endgroup$
add a comment |
$begingroup$
Compared to the temperatures encountered in lunar nights, the desired operating temperature of the James Webb Space Telescope is very low. Lunar nights are typically -170°C while the operating temperature of JWST is -220°C.
If surviving the cold lunar nights is difficult for the electronics, say on lunar rovers, then how does JWST overcome this issue?
And why not make use of the same methods adopted in JWST onboard the lunar rovers to survive lunar nights, avoiding the notorious nuclear heating?
rovers temperature james-webb-telescope lunar-module
$endgroup$
add a comment |
$begingroup$
Compared to the temperatures encountered in lunar nights, the desired operating temperature of the James Webb Space Telescope is very low. Lunar nights are typically -170°C while the operating temperature of JWST is -220°C.
If surviving the cold lunar nights is difficult for the electronics, say on lunar rovers, then how does JWST overcome this issue?
And why not make use of the same methods adopted in JWST onboard the lunar rovers to survive lunar nights, avoiding the notorious nuclear heating?
rovers temperature james-webb-telescope lunar-module
$endgroup$
Compared to the temperatures encountered in lunar nights, the desired operating temperature of the James Webb Space Telescope is very low. Lunar nights are typically -170°C while the operating temperature of JWST is -220°C.
If surviving the cold lunar nights is difficult for the electronics, say on lunar rovers, then how does JWST overcome this issue?
And why not make use of the same methods adopted in JWST onboard the lunar rovers to survive lunar nights, avoiding the notorious nuclear heating?
rovers temperature james-webb-telescope lunar-module
rovers temperature james-webb-telescope lunar-module
edited Jul 21 at 16:25
Steve Linton
10.6k1 gold badge27 silver badges55 bronze badges
10.6k1 gold badge27 silver badges55 bronze badges
asked Jul 20 at 15:08
karthikeyankarthikeyan
2,38215 silver badges33 bronze badges
2,38215 silver badges33 bronze badges
add a comment |
add a comment |
4 Answers
4
active
oldest
votes
$begingroup$
From Status of the JWST Sunshield and Spacecraft found in @Antzi
's answer:
Most of the electronics is on the "hot side" but there needs to be some conventional electronics on the cold side (beside the cooled IR sensor chips).
Small thermal environments on the cold side are equipped with heaters to provide mini-environments at normal operating temperature for these electronic devices.
[...]Thermostatically control heaters are used to
maintain equipment above minimum required temperature while under cold conditions. Heater drive electronics (HDE) controlled heaters are used to maintain the +J3 panel, propulsion lines, battery, star tracker, and 1 Hz isolators within the required stability range.
The spacecraft component temperatures are maintained within the required limits by the use of radiators, heat pipes, MLI, and heaters. Thermostat and software controlled heaters are the two types used on this spacecraft. The software control heaters are used to maintain tight temperature control for critical spacecraft components and structures. The heaters are controlled by flight software with temperature feedback control. The flight software enables the ground to modify any TCS mission constants which include on/off heater set-points and failure thresholds.
$endgroup$
add a comment |
$begingroup$
If surviving lunar nights are difficult to ensure the survival of the electronics, say on lunar rovers, in the low temperatures,
The temperature itself is not the primary reason.
Lunar nights are difficult to survive because you have 14 days of darkness. If you want to design a solar-powered rover that can store enough energy to stay warm for 14 days, the rover becomes large and heavy. Too heavy to launch with current rockets.
So we use nuclear decay heaters instead, which are much smaller and lighter.
The alternative is to power down for the lunar night. But then the entire rover cools down, and will heat up again the next morning. These heat cycles are the usual cause of death: because different materials expand and contract at different rates, it's really difficult to design electronics that stay intact with such large temperature swings.
JWST, on the other hand, is in permanent sunlight. This has several consequences:
- you can heat the electronics directly by putting them on the hot side of the spacecraft
- you can use electric power from the solar panels to run heaters on the cold side, without needing large batteries.
So you can't use the methods from JWST on a lunar rover: their environments are too different.
Nuclear heating isn't "notorious", it just makes the mission a bit more expensive. It's a mature, reliable technology that works, so why not use it?
$endgroup$
add a comment |
$begingroup$
Source: Me. I currently work as a systems engineer on JWST.
JWST will operating from the 2nd Lagrange Point (aka L2), which is approximately 1.5 million km (or 930,000 miles) past the Earth in Sun-Earth line. This is approximately 4x the distance from the Earth to the Moon. This distance, in addition to its lissajous orbit, ensure it will not encounter any Lunar Night, and its solar array will remain in sun.
Regarding its operational temperature, you have to understand JWST has three (3) clearly defined thermal regions, and a transitional region. Region 3 is the spacecraft compartment. This houses all the main spacecraft subsystems/electronics (main computer, communications system, attitude control, etc, as well as the main instrument computer and cryocoolers). This region is in continuous sun, so operates anywhere from 0-40 C, depending on the location in orbit and efficiency of thermal dissipation. The battery is also housed in Region 1, so will never experience the drastic cold.
With the 5-layer sunshield, there is a transition area to go from the "hot" sun side to the cryogenic cold side. Note that this is a very steep temperature transition, so materials and cabling have to withstand all this, plus the cryocooler lines.
Region 1 is the "cold" part of the observatory, and encompasses the mirrors and actuators and the instruments (meaning all their mechanical parts and their detectors), the support structure, and various heaters, harnesses, and thermal conductors. Here the temperature will passively reduce below 30 K, save for the heaters that keep the instruments at their operating temperatures, and the cryogenic instrument, which goes down to 6 K. The instrument mechanisms are all designed to work at these low temperatures, and the focal plane systems are also specially designed for these temperatures as well, with some immediate/local processing.
Region 2 is located off the back of Region 1. It contains the instrument electronics boxes (outside the main instrument computer), and a couple other support electronics boxes. This is a very-well insulated box with baseplate heaters to maintain it at >0 C, so compared to Region 1, it is quite warm! It also contains specialized, directional radiators that help shed heat from Region 1 into deep space for cooling down and maintaining operational temperature.
Keep in mind that all of these thermal regions are existing at the same time on JWST, although most of the electronics are kept fairly warm. Between 4 cryo-vacuum tests and a thermal vacuum test, the major components of all these have been successfully tested.
@GremlinWranger: Regarding thermal cycling and tin whiskers, NASA (and by extension, its contractors) require usage of specific solders and conformal coatings to mitigate tin whiskers and Paschen discharge. Additionally, once up there and everything has cooled to its operational temperature, JWSTs various regions will remain at their temperature within several kelvin (for heater cycling and seasonal/orbital effects), barring any incidents.
@uhoh: Thanks for the diagram and quoted text!
$endgroup$
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.
$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
add a comment |
$begingroup$
In terms of the electronics themselves many specific devices can operate at quite low temperatures, though any property depending on the physical dimension (resistance and capacitance) will change slightly due contraction. Some however explicitly cannot.
Batteries depend on chemical reactions that slow down approaching absolute zero and if all the elements are frozen. High capacity batteries also have micro structures that can get disrupted if ice crystals form due to freezing. This disruption can lead to short circuits when thawed again.
Some high value capacitors contain a fluid electrolytic which has similar results to those in batteries when frozen and thawed. They can generally be swapped with lower capacity varieties at a weight penalty.
Semiconductors change properties in various ways with temperature. In particular the resistance in the on state increases at low temperatures. This can handled by changing the doping of the parts and designing so that the part can function with a wide range of parameters but this increases size, weight, power consumption and design complexity. This pretty much rules out high performance processing while at very low temperatures but sensors and basic signal conditioning are possible.
High performance electronic parts involve a number of different materials (with different expansion coefficients) in electrical contact with each other, as noted in Hobbes' answer repeated cycling will produce failures over time if these loose connection. This can be reduced by careful design but involves increase in weight and complexity. Temperature cycling is also believed to be involved in tin whiskers that can create all sorts of complex problems.
$endgroup$
add a comment |
Your Answer
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "508"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fspace.stackexchange.com%2fquestions%2f37480%2fhow-can-electronics-on-board-jwst-survive-the-low-operating-temperature-while-it%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
From Status of the JWST Sunshield and Spacecraft found in @Antzi
's answer:
Most of the electronics is on the "hot side" but there needs to be some conventional electronics on the cold side (beside the cooled IR sensor chips).
Small thermal environments on the cold side are equipped with heaters to provide mini-environments at normal operating temperature for these electronic devices.
[...]Thermostatically control heaters are used to
maintain equipment above minimum required temperature while under cold conditions. Heater drive electronics (HDE) controlled heaters are used to maintain the +J3 panel, propulsion lines, battery, star tracker, and 1 Hz isolators within the required stability range.
The spacecraft component temperatures are maintained within the required limits by the use of radiators, heat pipes, MLI, and heaters. Thermostat and software controlled heaters are the two types used on this spacecraft. The software control heaters are used to maintain tight temperature control for critical spacecraft components and structures. The heaters are controlled by flight software with temperature feedback control. The flight software enables the ground to modify any TCS mission constants which include on/off heater set-points and failure thresholds.
$endgroup$
add a comment |
$begingroup$
From Status of the JWST Sunshield and Spacecraft found in @Antzi
's answer:
Most of the electronics is on the "hot side" but there needs to be some conventional electronics on the cold side (beside the cooled IR sensor chips).
Small thermal environments on the cold side are equipped with heaters to provide mini-environments at normal operating temperature for these electronic devices.
[...]Thermostatically control heaters are used to
maintain equipment above minimum required temperature while under cold conditions. Heater drive electronics (HDE) controlled heaters are used to maintain the +J3 panel, propulsion lines, battery, star tracker, and 1 Hz isolators within the required stability range.
The spacecraft component temperatures are maintained within the required limits by the use of radiators, heat pipes, MLI, and heaters. Thermostat and software controlled heaters are the two types used on this spacecraft. The software control heaters are used to maintain tight temperature control for critical spacecraft components and structures. The heaters are controlled by flight software with temperature feedback control. The flight software enables the ground to modify any TCS mission constants which include on/off heater set-points and failure thresholds.
$endgroup$
add a comment |
$begingroup$
From Status of the JWST Sunshield and Spacecraft found in @Antzi
's answer:
Most of the electronics is on the "hot side" but there needs to be some conventional electronics on the cold side (beside the cooled IR sensor chips).
Small thermal environments on the cold side are equipped with heaters to provide mini-environments at normal operating temperature for these electronic devices.
[...]Thermostatically control heaters are used to
maintain equipment above minimum required temperature while under cold conditions. Heater drive electronics (HDE) controlled heaters are used to maintain the +J3 panel, propulsion lines, battery, star tracker, and 1 Hz isolators within the required stability range.
The spacecraft component temperatures are maintained within the required limits by the use of radiators, heat pipes, MLI, and heaters. Thermostat and software controlled heaters are the two types used on this spacecraft. The software control heaters are used to maintain tight temperature control for critical spacecraft components and structures. The heaters are controlled by flight software with temperature feedback control. The flight software enables the ground to modify any TCS mission constants which include on/off heater set-points and failure thresholds.
$endgroup$
From Status of the JWST Sunshield and Spacecraft found in @Antzi
's answer:
Most of the electronics is on the "hot side" but there needs to be some conventional electronics on the cold side (beside the cooled IR sensor chips).
Small thermal environments on the cold side are equipped with heaters to provide mini-environments at normal operating temperature for these electronic devices.
[...]Thermostatically control heaters are used to
maintain equipment above minimum required temperature while under cold conditions. Heater drive electronics (HDE) controlled heaters are used to maintain the +J3 panel, propulsion lines, battery, star tracker, and 1 Hz isolators within the required stability range.
The spacecraft component temperatures are maintained within the required limits by the use of radiators, heat pipes, MLI, and heaters. Thermostat and software controlled heaters are the two types used on this spacecraft. The software control heaters are used to maintain tight temperature control for critical spacecraft components and structures. The heaters are controlled by flight software with temperature feedback control. The flight software enables the ground to modify any TCS mission constants which include on/off heater set-points and failure thresholds.
answered Jul 20 at 15:21
uhohuhoh
48.1k22 gold badges194 silver badges629 bronze badges
48.1k22 gold badges194 silver badges629 bronze badges
add a comment |
add a comment |
$begingroup$
If surviving lunar nights are difficult to ensure the survival of the electronics, say on lunar rovers, in the low temperatures,
The temperature itself is not the primary reason.
Lunar nights are difficult to survive because you have 14 days of darkness. If you want to design a solar-powered rover that can store enough energy to stay warm for 14 days, the rover becomes large and heavy. Too heavy to launch with current rockets.
So we use nuclear decay heaters instead, which are much smaller and lighter.
The alternative is to power down for the lunar night. But then the entire rover cools down, and will heat up again the next morning. These heat cycles are the usual cause of death: because different materials expand and contract at different rates, it's really difficult to design electronics that stay intact with such large temperature swings.
JWST, on the other hand, is in permanent sunlight. This has several consequences:
- you can heat the electronics directly by putting them on the hot side of the spacecraft
- you can use electric power from the solar panels to run heaters on the cold side, without needing large batteries.
So you can't use the methods from JWST on a lunar rover: their environments are too different.
Nuclear heating isn't "notorious", it just makes the mission a bit more expensive. It's a mature, reliable technology that works, so why not use it?
$endgroup$
add a comment |
$begingroup$
If surviving lunar nights are difficult to ensure the survival of the electronics, say on lunar rovers, in the low temperatures,
The temperature itself is not the primary reason.
Lunar nights are difficult to survive because you have 14 days of darkness. If you want to design a solar-powered rover that can store enough energy to stay warm for 14 days, the rover becomes large and heavy. Too heavy to launch with current rockets.
So we use nuclear decay heaters instead, which are much smaller and lighter.
The alternative is to power down for the lunar night. But then the entire rover cools down, and will heat up again the next morning. These heat cycles are the usual cause of death: because different materials expand and contract at different rates, it's really difficult to design electronics that stay intact with such large temperature swings.
JWST, on the other hand, is in permanent sunlight. This has several consequences:
- you can heat the electronics directly by putting them on the hot side of the spacecraft
- you can use electric power from the solar panels to run heaters on the cold side, without needing large batteries.
So you can't use the methods from JWST on a lunar rover: their environments are too different.
Nuclear heating isn't "notorious", it just makes the mission a bit more expensive. It's a mature, reliable technology that works, so why not use it?
$endgroup$
add a comment |
$begingroup$
If surviving lunar nights are difficult to ensure the survival of the electronics, say on lunar rovers, in the low temperatures,
The temperature itself is not the primary reason.
Lunar nights are difficult to survive because you have 14 days of darkness. If you want to design a solar-powered rover that can store enough energy to stay warm for 14 days, the rover becomes large and heavy. Too heavy to launch with current rockets.
So we use nuclear decay heaters instead, which are much smaller and lighter.
The alternative is to power down for the lunar night. But then the entire rover cools down, and will heat up again the next morning. These heat cycles are the usual cause of death: because different materials expand and contract at different rates, it's really difficult to design electronics that stay intact with such large temperature swings.
JWST, on the other hand, is in permanent sunlight. This has several consequences:
- you can heat the electronics directly by putting them on the hot side of the spacecraft
- you can use electric power from the solar panels to run heaters on the cold side, without needing large batteries.
So you can't use the methods from JWST on a lunar rover: their environments are too different.
Nuclear heating isn't "notorious", it just makes the mission a bit more expensive. It's a mature, reliable technology that works, so why not use it?
$endgroup$
If surviving lunar nights are difficult to ensure the survival of the electronics, say on lunar rovers, in the low temperatures,
The temperature itself is not the primary reason.
Lunar nights are difficult to survive because you have 14 days of darkness. If you want to design a solar-powered rover that can store enough energy to stay warm for 14 days, the rover becomes large and heavy. Too heavy to launch with current rockets.
So we use nuclear decay heaters instead, which are much smaller and lighter.
The alternative is to power down for the lunar night. But then the entire rover cools down, and will heat up again the next morning. These heat cycles are the usual cause of death: because different materials expand and contract at different rates, it's really difficult to design electronics that stay intact with such large temperature swings.
JWST, on the other hand, is in permanent sunlight. This has several consequences:
- you can heat the electronics directly by putting them on the hot side of the spacecraft
- you can use electric power from the solar panels to run heaters on the cold side, without needing large batteries.
So you can't use the methods from JWST on a lunar rover: their environments are too different.
Nuclear heating isn't "notorious", it just makes the mission a bit more expensive. It's a mature, reliable technology that works, so why not use it?
answered Jul 20 at 17:31
HobbesHobbes
103k2 gold badges300 silver badges459 bronze badges
103k2 gold badges300 silver badges459 bronze badges
add a comment |
add a comment |
$begingroup$
Source: Me. I currently work as a systems engineer on JWST.
JWST will operating from the 2nd Lagrange Point (aka L2), which is approximately 1.5 million km (or 930,000 miles) past the Earth in Sun-Earth line. This is approximately 4x the distance from the Earth to the Moon. This distance, in addition to its lissajous orbit, ensure it will not encounter any Lunar Night, and its solar array will remain in sun.
Regarding its operational temperature, you have to understand JWST has three (3) clearly defined thermal regions, and a transitional region. Region 3 is the spacecraft compartment. This houses all the main spacecraft subsystems/electronics (main computer, communications system, attitude control, etc, as well as the main instrument computer and cryocoolers). This region is in continuous sun, so operates anywhere from 0-40 C, depending on the location in orbit and efficiency of thermal dissipation. The battery is also housed in Region 1, so will never experience the drastic cold.
With the 5-layer sunshield, there is a transition area to go from the "hot" sun side to the cryogenic cold side. Note that this is a very steep temperature transition, so materials and cabling have to withstand all this, plus the cryocooler lines.
Region 1 is the "cold" part of the observatory, and encompasses the mirrors and actuators and the instruments (meaning all their mechanical parts and their detectors), the support structure, and various heaters, harnesses, and thermal conductors. Here the temperature will passively reduce below 30 K, save for the heaters that keep the instruments at their operating temperatures, and the cryogenic instrument, which goes down to 6 K. The instrument mechanisms are all designed to work at these low temperatures, and the focal plane systems are also specially designed for these temperatures as well, with some immediate/local processing.
Region 2 is located off the back of Region 1. It contains the instrument electronics boxes (outside the main instrument computer), and a couple other support electronics boxes. This is a very-well insulated box with baseplate heaters to maintain it at >0 C, so compared to Region 1, it is quite warm! It also contains specialized, directional radiators that help shed heat from Region 1 into deep space for cooling down and maintaining operational temperature.
Keep in mind that all of these thermal regions are existing at the same time on JWST, although most of the electronics are kept fairly warm. Between 4 cryo-vacuum tests and a thermal vacuum test, the major components of all these have been successfully tested.
@GremlinWranger: Regarding thermal cycling and tin whiskers, NASA (and by extension, its contractors) require usage of specific solders and conformal coatings to mitigate tin whiskers and Paschen discharge. Additionally, once up there and everything has cooled to its operational temperature, JWSTs various regions will remain at their temperature within several kelvin (for heater cycling and seasonal/orbital effects), barring any incidents.
@uhoh: Thanks for the diagram and quoted text!
$endgroup$
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.
$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
add a comment |
$begingroup$
Source: Me. I currently work as a systems engineer on JWST.
JWST will operating from the 2nd Lagrange Point (aka L2), which is approximately 1.5 million km (or 930,000 miles) past the Earth in Sun-Earth line. This is approximately 4x the distance from the Earth to the Moon. This distance, in addition to its lissajous orbit, ensure it will not encounter any Lunar Night, and its solar array will remain in sun.
Regarding its operational temperature, you have to understand JWST has three (3) clearly defined thermal regions, and a transitional region. Region 3 is the spacecraft compartment. This houses all the main spacecraft subsystems/electronics (main computer, communications system, attitude control, etc, as well as the main instrument computer and cryocoolers). This region is in continuous sun, so operates anywhere from 0-40 C, depending on the location in orbit and efficiency of thermal dissipation. The battery is also housed in Region 1, so will never experience the drastic cold.
With the 5-layer sunshield, there is a transition area to go from the "hot" sun side to the cryogenic cold side. Note that this is a very steep temperature transition, so materials and cabling have to withstand all this, plus the cryocooler lines.
Region 1 is the "cold" part of the observatory, and encompasses the mirrors and actuators and the instruments (meaning all their mechanical parts and their detectors), the support structure, and various heaters, harnesses, and thermal conductors. Here the temperature will passively reduce below 30 K, save for the heaters that keep the instruments at their operating temperatures, and the cryogenic instrument, which goes down to 6 K. The instrument mechanisms are all designed to work at these low temperatures, and the focal plane systems are also specially designed for these temperatures as well, with some immediate/local processing.
Region 2 is located off the back of Region 1. It contains the instrument electronics boxes (outside the main instrument computer), and a couple other support electronics boxes. This is a very-well insulated box with baseplate heaters to maintain it at >0 C, so compared to Region 1, it is quite warm! It also contains specialized, directional radiators that help shed heat from Region 1 into deep space for cooling down and maintaining operational temperature.
Keep in mind that all of these thermal regions are existing at the same time on JWST, although most of the electronics are kept fairly warm. Between 4 cryo-vacuum tests and a thermal vacuum test, the major components of all these have been successfully tested.
@GremlinWranger: Regarding thermal cycling and tin whiskers, NASA (and by extension, its contractors) require usage of specific solders and conformal coatings to mitigate tin whiskers and Paschen discharge. Additionally, once up there and everything has cooled to its operational temperature, JWSTs various regions will remain at their temperature within several kelvin (for heater cycling and seasonal/orbital effects), barring any incidents.
@uhoh: Thanks for the diagram and quoted text!
$endgroup$
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.
$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
add a comment |
$begingroup$
Source: Me. I currently work as a systems engineer on JWST.
JWST will operating from the 2nd Lagrange Point (aka L2), which is approximately 1.5 million km (or 930,000 miles) past the Earth in Sun-Earth line. This is approximately 4x the distance from the Earth to the Moon. This distance, in addition to its lissajous orbit, ensure it will not encounter any Lunar Night, and its solar array will remain in sun.
Regarding its operational temperature, you have to understand JWST has three (3) clearly defined thermal regions, and a transitional region. Region 3 is the spacecraft compartment. This houses all the main spacecraft subsystems/electronics (main computer, communications system, attitude control, etc, as well as the main instrument computer and cryocoolers). This region is in continuous sun, so operates anywhere from 0-40 C, depending on the location in orbit and efficiency of thermal dissipation. The battery is also housed in Region 1, so will never experience the drastic cold.
With the 5-layer sunshield, there is a transition area to go from the "hot" sun side to the cryogenic cold side. Note that this is a very steep temperature transition, so materials and cabling have to withstand all this, plus the cryocooler lines.
Region 1 is the "cold" part of the observatory, and encompasses the mirrors and actuators and the instruments (meaning all their mechanical parts and their detectors), the support structure, and various heaters, harnesses, and thermal conductors. Here the temperature will passively reduce below 30 K, save for the heaters that keep the instruments at their operating temperatures, and the cryogenic instrument, which goes down to 6 K. The instrument mechanisms are all designed to work at these low temperatures, and the focal plane systems are also specially designed for these temperatures as well, with some immediate/local processing.
Region 2 is located off the back of Region 1. It contains the instrument electronics boxes (outside the main instrument computer), and a couple other support electronics boxes. This is a very-well insulated box with baseplate heaters to maintain it at >0 C, so compared to Region 1, it is quite warm! It also contains specialized, directional radiators that help shed heat from Region 1 into deep space for cooling down and maintaining operational temperature.
Keep in mind that all of these thermal regions are existing at the same time on JWST, although most of the electronics are kept fairly warm. Between 4 cryo-vacuum tests and a thermal vacuum test, the major components of all these have been successfully tested.
@GremlinWranger: Regarding thermal cycling and tin whiskers, NASA (and by extension, its contractors) require usage of specific solders and conformal coatings to mitigate tin whiskers and Paschen discharge. Additionally, once up there and everything has cooled to its operational temperature, JWSTs various regions will remain at their temperature within several kelvin (for heater cycling and seasonal/orbital effects), barring any incidents.
@uhoh: Thanks for the diagram and quoted text!
$endgroup$
Source: Me. I currently work as a systems engineer on JWST.
JWST will operating from the 2nd Lagrange Point (aka L2), which is approximately 1.5 million km (or 930,000 miles) past the Earth in Sun-Earth line. This is approximately 4x the distance from the Earth to the Moon. This distance, in addition to its lissajous orbit, ensure it will not encounter any Lunar Night, and its solar array will remain in sun.
Regarding its operational temperature, you have to understand JWST has three (3) clearly defined thermal regions, and a transitional region. Region 3 is the spacecraft compartment. This houses all the main spacecraft subsystems/electronics (main computer, communications system, attitude control, etc, as well as the main instrument computer and cryocoolers). This region is in continuous sun, so operates anywhere from 0-40 C, depending on the location in orbit and efficiency of thermal dissipation. The battery is also housed in Region 1, so will never experience the drastic cold.
With the 5-layer sunshield, there is a transition area to go from the "hot" sun side to the cryogenic cold side. Note that this is a very steep temperature transition, so materials and cabling have to withstand all this, plus the cryocooler lines.
Region 1 is the "cold" part of the observatory, and encompasses the mirrors and actuators and the instruments (meaning all their mechanical parts and their detectors), the support structure, and various heaters, harnesses, and thermal conductors. Here the temperature will passively reduce below 30 K, save for the heaters that keep the instruments at their operating temperatures, and the cryogenic instrument, which goes down to 6 K. The instrument mechanisms are all designed to work at these low temperatures, and the focal plane systems are also specially designed for these temperatures as well, with some immediate/local processing.
Region 2 is located off the back of Region 1. It contains the instrument electronics boxes (outside the main instrument computer), and a couple other support electronics boxes. This is a very-well insulated box with baseplate heaters to maintain it at >0 C, so compared to Region 1, it is quite warm! It also contains specialized, directional radiators that help shed heat from Region 1 into deep space for cooling down and maintaining operational temperature.
Keep in mind that all of these thermal regions are existing at the same time on JWST, although most of the electronics are kept fairly warm. Between 4 cryo-vacuum tests and a thermal vacuum test, the major components of all these have been successfully tested.
@GremlinWranger: Regarding thermal cycling and tin whiskers, NASA (and by extension, its contractors) require usage of specific solders and conformal coatings to mitigate tin whiskers and Paschen discharge. Additionally, once up there and everything has cooled to its operational temperature, JWSTs various regions will remain at their temperature within several kelvin (for heater cycling and seasonal/orbital effects), barring any incidents.
@uhoh: Thanks for the diagram and quoted text!
answered Jul 22 at 2:51
sohowsgoingsohowsgoing
1812 bronze badges
1812 bronze badges
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.
$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
add a comment |
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.
$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
Thanks for your detailed and authoritative answer and Welcome to Space! just fyi the question Can the James Webb Space Telescope basically manage its own orbit if necessary? might be in need of an updated answer as well.
$endgroup$
– uhoh
Jul 22 at 23:10
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the
@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
also fyi, now that you have more than 50 reputation points, you can leave comments under other people's posts. You've formatted the
@replies
feature (found in FAQ on the main meta site) properly but they don't work in the body of a post, they only work in comments below posts, or in chat, such as the Pod Bay. You can try posting your message to GremlinWrangler as a comment now.$endgroup$
– uhoh
Jul 22 at 23:13
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Hey! I also wanted to welcome you :)! It's always awesome to hear it from the horses mouth, so to speak. Would love to hear more from you! Thanks for taking the time to talk to us, we all appreciate it.
$endgroup$
– Magic Octopus Urn
Jul 23 at 19:17
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
$begingroup$
Thank you! I can see what I can help out on here and there, but no promises I'll know everything. This agency is a good size and there are many, many people smarter than me working on things! I can try to answer any questions you have that are within my ability and/or capability
$endgroup$
– sohowsgoing
Jul 24 at 17:49
add a comment |
$begingroup$
In terms of the electronics themselves many specific devices can operate at quite low temperatures, though any property depending on the physical dimension (resistance and capacitance) will change slightly due contraction. Some however explicitly cannot.
Batteries depend on chemical reactions that slow down approaching absolute zero and if all the elements are frozen. High capacity batteries also have micro structures that can get disrupted if ice crystals form due to freezing. This disruption can lead to short circuits when thawed again.
Some high value capacitors contain a fluid electrolytic which has similar results to those in batteries when frozen and thawed. They can generally be swapped with lower capacity varieties at a weight penalty.
Semiconductors change properties in various ways with temperature. In particular the resistance in the on state increases at low temperatures. This can handled by changing the doping of the parts and designing so that the part can function with a wide range of parameters but this increases size, weight, power consumption and design complexity. This pretty much rules out high performance processing while at very low temperatures but sensors and basic signal conditioning are possible.
High performance electronic parts involve a number of different materials (with different expansion coefficients) in electrical contact with each other, as noted in Hobbes' answer repeated cycling will produce failures over time if these loose connection. This can be reduced by careful design but involves increase in weight and complexity. Temperature cycling is also believed to be involved in tin whiskers that can create all sorts of complex problems.
$endgroup$
add a comment |
$begingroup$
In terms of the electronics themselves many specific devices can operate at quite low temperatures, though any property depending on the physical dimension (resistance and capacitance) will change slightly due contraction. Some however explicitly cannot.
Batteries depend on chemical reactions that slow down approaching absolute zero and if all the elements are frozen. High capacity batteries also have micro structures that can get disrupted if ice crystals form due to freezing. This disruption can lead to short circuits when thawed again.
Some high value capacitors contain a fluid electrolytic which has similar results to those in batteries when frozen and thawed. They can generally be swapped with lower capacity varieties at a weight penalty.
Semiconductors change properties in various ways with temperature. In particular the resistance in the on state increases at low temperatures. This can handled by changing the doping of the parts and designing so that the part can function with a wide range of parameters but this increases size, weight, power consumption and design complexity. This pretty much rules out high performance processing while at very low temperatures but sensors and basic signal conditioning are possible.
High performance electronic parts involve a number of different materials (with different expansion coefficients) in electrical contact with each other, as noted in Hobbes' answer repeated cycling will produce failures over time if these loose connection. This can be reduced by careful design but involves increase in weight and complexity. Temperature cycling is also believed to be involved in tin whiskers that can create all sorts of complex problems.
$endgroup$
add a comment |
$begingroup$
In terms of the electronics themselves many specific devices can operate at quite low temperatures, though any property depending on the physical dimension (resistance and capacitance) will change slightly due contraction. Some however explicitly cannot.
Batteries depend on chemical reactions that slow down approaching absolute zero and if all the elements are frozen. High capacity batteries also have micro structures that can get disrupted if ice crystals form due to freezing. This disruption can lead to short circuits when thawed again.
Some high value capacitors contain a fluid electrolytic which has similar results to those in batteries when frozen and thawed. They can generally be swapped with lower capacity varieties at a weight penalty.
Semiconductors change properties in various ways with temperature. In particular the resistance in the on state increases at low temperatures. This can handled by changing the doping of the parts and designing so that the part can function with a wide range of parameters but this increases size, weight, power consumption and design complexity. This pretty much rules out high performance processing while at very low temperatures but sensors and basic signal conditioning are possible.
High performance electronic parts involve a number of different materials (with different expansion coefficients) in electrical contact with each other, as noted in Hobbes' answer repeated cycling will produce failures over time if these loose connection. This can be reduced by careful design but involves increase in weight and complexity. Temperature cycling is also believed to be involved in tin whiskers that can create all sorts of complex problems.
$endgroup$
In terms of the electronics themselves many specific devices can operate at quite low temperatures, though any property depending on the physical dimension (resistance and capacitance) will change slightly due contraction. Some however explicitly cannot.
Batteries depend on chemical reactions that slow down approaching absolute zero and if all the elements are frozen. High capacity batteries also have micro structures that can get disrupted if ice crystals form due to freezing. This disruption can lead to short circuits when thawed again.
Some high value capacitors contain a fluid electrolytic which has similar results to those in batteries when frozen and thawed. They can generally be swapped with lower capacity varieties at a weight penalty.
Semiconductors change properties in various ways with temperature. In particular the resistance in the on state increases at low temperatures. This can handled by changing the doping of the parts and designing so that the part can function with a wide range of parameters but this increases size, weight, power consumption and design complexity. This pretty much rules out high performance processing while at very low temperatures but sensors and basic signal conditioning are possible.
High performance electronic parts involve a number of different materials (with different expansion coefficients) in electrical contact with each other, as noted in Hobbes' answer repeated cycling will produce failures over time if these loose connection. This can be reduced by careful design but involves increase in weight and complexity. Temperature cycling is also believed to be involved in tin whiskers that can create all sorts of complex problems.
answered Jul 20 at 23:41
GremlinWrangerGremlinWranger
3,6064 silver badges20 bronze badges
3,6064 silver badges20 bronze badges
add a comment |
add a comment |
Thanks for contributing an answer to Space Exploration Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fspace.stackexchange.com%2fquestions%2f37480%2fhow-can-electronics-on-board-jwst-survive-the-low-operating-temperature-while-it%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
oRh5gcf0 h6Cw0b3tF0W l,vPYu2G4qEbNJCOISmGP