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Whenever I see an article like this and something at nasa has broken, it seems like they always are soliciting a new project. It makes me wonder, why not just b

Whenever I see an article like this and something at nasa has broken, it seems like they always are soliciting a new project. It makes me wonder, why not just build the exact same thing again (with the broken parts fixed, of course)?

deleted 13y ago
[deleted]
jerrya 13y ago
Building a new something that was designed, built, tested and launched quite a while ago is difficult because a lot of knowledge of the processes have been lost, along with tooling, supplies, etc. However, I do wonder why they build 1 Kepler space telescope and not 2, or 3, and then store the already built ones until they are wanted.
- mturmon 13y ago
  Given what the previous instrument taught us, the science questions change, so the instruments you need also change. For instance, it surprised everyone when it turned out that most stars are more variable than the Sun is, and this extra variability has complicated the Kepler data analysis. Additionally, you can incorporate lessons learned (from an engineering perspective, not science) into the next instrument. Some things work well and are preserved, and others don't. Here's a link to some tech awards relevant to future exoplanet instruments: http://exep.jpl.nasa.gov/technology/ http://exep.jpl.nasa.gov/technology/
- sigstoat 13y ago
  kepler wasn't built that long ago, as these things go. and ball aerospace which designed and built it is already designing and building an almost identical spacecraft for the b612 foundation. so of all the spacecraft you might want to duplicate, kepler would be a really easy one at the moment.
  - CamperBob2 13y ago
    Interesting, I'd never heard of B612. So they're sufficiently well-funded to commission a $500M Kepler-class probe?
    - sigstoat 13y ago
      last i'd heard they were still trying to get more silicon valley bigwigs funding it. ball was treating them as a sufficiently "real" customer that it was talking to subcontractors about the mission, but i hadn't heard about any big checks for hardware being cut.
- ak217 13y ago
  As sigstoat said, Kepler is a fairly recent spacecraft. And yeah, it's interesting that they don't treat spacecraft like this as small-batch production runs. The incremental cost of producing 5 Kepler replicas and keeping equipment and processes documented at the time of initial production seems very small compared to doing the same project all over again a decade later. Even if they have to do some major changes, I imagine having a ready to go spacecraft helps. On the flipside, I guess the arguments for componentization apply. If off-the-shelf components are improving all the time, integrating them into a full spacecraft should be getting cheaper and easier over time. What I really wonder about is, given how troublesome and relatively lightweight gyros are, why didn't they have more spares?
MichaelMoser123 13y ago
Can they possibly fix it? They don't have a Shuttle to take the thing in so it can be brought back and fixed. Whatever they say about the Shuttle, it was a powerful vehicle. Can a robot fix the thing?
- sigstoat 13y ago
  i don't think he was talking about fixing kepler. just building a new, less-shitty one. and however "powerful" the shuttle was, it couldn't get to something 3 light-minutes away (which was kepler's distance, the last time i looked)
  - MichaelMoser123 13y ago
    So Armageddon was impossible? I am disappointed. http://en.wikipedia.org/wiki/Armageddon_(1998_film) http://en.wikipedia.org/wiki/Armageddon_(1998_film) "American Components, Russian Components, all the same, all made in Taiwan!"
    - jlgreco 13y ago
      IIRC the Space Shuttles used in Aermageddon were not "the" space shuttles, but some hypothetical semi-secret project shuttles that the movie made up. But yeah, the space shuttles were LEO only. IIRC the highest they ever went was up to Hubble, and I think that was pretty close to the most they could manage. Though now that I think about it, I am pretty sure they generally jettisoned the external fuel tanks with a little fuel left over, maybe they could delay the jettison to get into slightly higher orbits than usual.
- Moto7451 13y ago
  Kepler actually orbits the Sun, not the Earth[1]. Its orbit is slower than the Earth's and as a result is getting farther away from the Earth. Assuming it needs an EVA to fix, as Hubble did, it's impossible to fix as we lack a manned spacecraft capable of getting there. [1]http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_orbit_and_orientation http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_...
InclinedPlane 13y ago
Budgeting and launch costs are probably the biggest reasons. Kepler, for example, has already used up its budget to build, launch, and operate the telescope for several years. Even if free replacement hardware was available there may not be enough money to launch it. Also, the way most spacecraft are built is as one off prototypes, so building another copy, even if all the spare parts were available, is a very non-trivial endeavor. Even if it didn't take as long as building the original it would still be fairly expensive just to go through all of the necessary testing and integration steps. The end result of all of this is that it rarely makes sense to spend the time and money to refly a spacecraft and instead it usually makes more sense to simply forge ahead and seek funding for a follow-on mission of a new design. Here's a few case studies. The inaugural launch of the Ariane 5 rocket failed, which resulted in the loss of 4 "Cluster" spacecraft which were designed to study Earth's magnetosphere (a loss of about $370 million in hardware). However, ESA decided to fund replacements and they built 4 new satellites, making use of flight spares and extra hardware to save on costs, and then launched the new satellites on 2 separate Soyuz-Fregat flights. However, it still cost almost as much money to launch Cluster II as for the originals, so this was a rather heroic effort on ESA's part. In 1999 the Wide Field Infrared Explorer (WIRE) spacecraft was launched, shortly after launch there was a malfunction that caused a loss of the main science instrument on the orbital telescope. The mission was not replaced. However, the loss of WIRE caused other IR survey mission proposals to receive greater interest, which led to the funding of the "Next Generation Sky Survey" Medium-class Explorer mission. This infrared full-sky survey mission was launched in 2009 (as WISE, the Wide-field Infrared Survey Explorer) and achieved all of the science goals of the original WIRE mission. In 1993 all contact was lost with the Mars Observer spacecraft right at the moment of planned orbital insertion. This loss led to a re-evaluation of the unmanned Mars exploration program at NASA and eventually led to around 10 new missions to Mars over the following 2 decades, most of them successful.
jbri 13y ago
In general, I'd expect that you learn a lot in the process of building and flying a spacecraft, even if it ultimately fails to meet its objective. If you're going to have to launch a new spacecraft anyway, why not take some of those lessons into account when you build the next one?
caf 13y ago
The impression I had from the article is that they're soliciting new projects that make use of the broken Kepler. It's not completely cactus, it just can't fulfil its original mission anymore. This strikes me as an excellent thing to do - if they can find a project that can fund the ongoing costs of Kepler, then it makes sense to reuse it.
ngoldbaum 13y ago
No one else has brought up that another Kepler wouldn't necessarily be as impactful as the original. True, it would probably discover another couple thousand planets, but Kepler has already done that once. What's another factor of two in the number of known planets? Kepler looks off the plane of the Galaxy at stars that are typically several kiloparsecs away. In other words, we are never going to visit these worlds. Now that Kepler has revealed that planets are common, it will be much more interesting to find nearby planets that we have a better chance of characterizing, seding probes to, or even visiting one day. This is what TESS will do: http://en.wikipedia.org/wiki/Transiting_Exoplanet_Survey_Satellite http://en.wikipedia.org/wiki/Transiting_Exoplanet_Survey_Sat...

deleted 13y ago

[deleted]

jerrya 13y ago

Building a new something that was designed, built, tested and launched quite a while ago is difficult because a lot of knowledge of the processes have been lost, along with tooling, supplies, etc. However, I do wonder why they build 1 Kepler space telescope and not 2, or 3, and then store the already built ones until they are wanted.

mturmon 13y ago
Given what the previous instrument taught us, the science questions change, so the instruments you need also change. For instance, it surprised everyone when it turned out that most stars are more variable than the Sun is, and this extra variability has complicated the Kepler data analysis. Additionally, you can incorporate lessons learned (from an engineering perspective, not science) into the next instrument. Some things work well and are preserved, and others don't. Here's a link to some tech awards relevant to future exoplanet instruments: http://exep.jpl.nasa.gov/technology/ http://exep.jpl.nasa.gov/technology/
sigstoat 13y ago
kepler wasn't built that long ago, as these things go. and ball aerospace which designed and built it is already designing and building an almost identical spacecraft for the b612 foundation. so of all the spacecraft you might want to duplicate, kepler would be a really easy one at the moment.
- CamperBob2 13y ago
  Interesting, I'd never heard of B612. So they're sufficiently well-funded to commission a $500M Kepler-class probe?
  - sigstoat 13y ago
    last i'd heard they were still trying to get more silicon valley bigwigs funding it. ball was treating them as a sufficiently "real" customer that it was talking to subcontractors about the mission, but i hadn't heard about any big checks for hardware being cut.
ak217 13y ago
As sigstoat said, Kepler is a fairly recent spacecraft. And yeah, it's interesting that they don't treat spacecraft like this as small-batch production runs. The incremental cost of producing 5 Kepler replicas and keeping equipment and processes documented at the time of initial production seems very small compared to doing the same project all over again a decade later. Even if they have to do some major changes, I imagine having a ready to go spacecraft helps. On the flipside, I guess the arguments for componentization apply. If off-the-shelf components are improving all the time, integrating them into a full spacecraft should be getting cheaper and easier over time. What I really wonder about is, given how troublesome and relatively lightweight gyros are, why didn't they have more spares?

MichaelMoser123 13y ago

Can they possibly fix it? They don't have a Shuttle to take the thing in so it can be brought back and fixed. Whatever they say about the Shuttle, it was a powerful vehicle. Can a robot fix the thing?

sigstoat 13y ago
i don't think he was talking about fixing kepler. just building a new, less-shitty one. and however "powerful" the shuttle was, it couldn't get to something 3 light-minutes away (which was kepler's distance, the last time i looked)
- MichaelMoser123 13y ago
  So Armageddon was impossible? I am disappointed. http://en.wikipedia.org/wiki/Armageddon_(1998_film) http://en.wikipedia.org/wiki/Armageddon_(1998_film) "American Components, Russian Components, all the same, all made in Taiwan!"
  - jlgreco 13y ago
    IIRC the Space Shuttles used in Aermageddon were not "the" space shuttles, but some hypothetical semi-secret project shuttles that the movie made up. But yeah, the space shuttles were LEO only. IIRC the highest they ever went was up to Hubble, and I think that was pretty close to the most they could manage. Though now that I think about it, I am pretty sure they generally jettisoned the external fuel tanks with a little fuel left over, maybe they could delay the jettison to get into slightly higher orbits than usual.
Moto7451 13y ago
Kepler actually orbits the Sun, not the Earth[1]. Its orbit is slower than the Earth's and as a result is getting farther away from the Earth. Assuming it needs an EVA to fix, as Hubble did, it's impossible to fix as we lack a manned spacecraft capable of getting there. [1]http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_orbit_and_orientation http://en.wikipedia.org/wiki/Kepler_(spacecraft)#Spacecraft_...

InclinedPlane 13y ago

Budgeting and launch costs are probably the biggest reasons. Kepler, for example, has already used up its budget to build, launch, and operate the telescope for several years. Even if free replacement hardware was available there may not be enough money to launch it. Also, the way most spacecraft are built is as one off prototypes, so building another copy, even if all the spare parts were available, is a very non-trivial endeavor. Even if it didn't take as long as building the original it would still be fairly expensive just to go through all of the necessary testing and integration steps. The end result of all of this is that it rarely makes sense to spend the time and money to refly a spacecraft and instead it usually makes more sense to simply forge ahead and seek funding for a follow-on mission of a new design. Here's a few case studies. The inaugural launch of the Ariane 5 rocket failed, which resulted in the loss of 4 "Cluster" spacecraft which were designed to study Earth's magnetosphere (a loss of about $370 million in hardware). However, ESA decided to fund replacements and they built 4 new satellites, making use of flight spares and extra hardware to save on costs, and then launched the new satellites on 2 separate Soyuz-Fregat flights. However, it still cost almost as much money to launch Cluster II as for the originals, so this was a rather heroic effort on ESA's part. In 1999 the Wide Field Infrared Explorer (WIRE) spacecraft was launched, shortly after launch there was a malfunction that caused a loss of the main science instrument on the orbital telescope. The mission was not replaced. However, the loss of WIRE caused other IR survey mission proposals to receive greater interest, which led to the funding of the "Next Generation Sky Survey" Medium-class Explorer mission. This infrared full-sky survey mission was launched in 2009 (as WISE, the Wide-field Infrared Survey Explorer) and achieved all of the science goals of the original WIRE mission. In 1993 all contact was lost with the Mars Observer spacecraft right at the moment of planned orbital insertion. This loss led to a re-evaluation of the unmanned Mars exploration program at NASA and eventually led to around 10 new missions to Mars over the following 2 decades, most of them successful.

jbri 13y ago

In general, I'd expect that you learn a lot in the process of building and flying a spacecraft, even if it ultimately fails to meet its objective. If you're going to have to launch a new spacecraft anyway, why not take some of those lessons into account when you build the next one?

caf 13y ago

The impression I had from the article is that they're soliciting new projects that make use of the broken Kepler. It's not completely cactus, it just can't fulfil its original mission anymore. This strikes me as an excellent thing to do - if they can find a project that can fund the ongoing costs of Kepler, then it makes sense to reuse it.

ngoldbaum 13y ago

No one else has brought up that another Kepler wouldn't necessarily be as impactful as the original. True, it would probably discover another couple thousand planets, but Kepler has already done that once. What's another factor of two in the number of known planets? Kepler looks off the plane of the Galaxy at stars that are typically several kiloparsecs away. In other words, we are never going to visit these worlds. Now that Kepler has revealed that planets are common, it will be much more interesting to find nearby planets that we have a better chance of characterizing, seding probes to, or even visiting one day. This is what TESS will do: http://en.wikipedia.org/wiki/Transiting_Exoplanet_Survey_Satellite http://en.wikipedia.org/wiki/Transiting_Exoplanet_Survey_Sat...