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Nasa Establishes Contact with STEREO Mission

nasa.gov

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Re: Nasa Establishes Contact with STEREO Mission

#11

Post by mikeash »

codezero wrote: post #3
spuz wrote: post #2

The linked article that gives the background on this mission and its recovery is definitely worth reading [0]. In particular, it's worth noting that the STEREO mission was only supposed to last until 2008 and part of the reason it was lost was due to NASA's attempts to reconfigure it to survive the unplanned period it would be out of contact from Earth as it passed behind the Sun. It would be pretty impressive if the…

I imagine this happens more often than most people realize. I worked on a satellite that was launched in 2003 and had a lifetime of 3 years. It operated until at least 2012 when the Air Force decided it was done paying for the downlink, but the satellite itself was still in pretty good condition.

I always assumed this happened because the official lifetime is defined in terms of some high probability of surviving that long, maybe 95%. And if you have a 95% chance of lasting 3 years, you probably have something like a 50% chance of lasting a decade or two. Is that assessment vaguely correct?

Re: Nasa Establishes Contact with STEREO Mission

#12

Post by codezero »

mikeash wrote: post #11
codezero wrote: post #3

Earlier quoted context omitted.

I imagine this happens more often than most people realize. I worked on a satellite that was launched in 2003 and had a lifetime of 3 years. It operated until at least 2012 when the Air Force decided it was done paying for the downlink, but the satellite itself was still in pretty good condition.

I always assumed this happened because the official lifetime is defined in terms of some high probability of surviving that long, maybe 95%. And if you have a 95% chance of lasting 3 years, you probably have something like a 50% chance of lasting a decade or two. Is that assessment vaguely correct?

Pretty much. The larger factor is whether you can continue to get funding beyond the end of life.

Re: Nasa Establishes Contact with STEREO Mission

#13

Post by kylek »

Slightly off-topic, but if you're in to solar/space weather news, I highly recommend you take a look at the suspicious0bservers channel on youtube. Ben does a daily 5-minute blurb on this science-y kind of stuff (stereo has been mentioned a bit of the last few days). Very interesting and not a big time commitment.

https://www.youtube.com/user/Suspicious0bservers

(Today's news, mentioning the return of stereo https://www.youtube.com/watch?v=MhSCMR0YP8Q )

Re: Nasa Establishes Contact with STEREO Mission

#14

Post by daveloyall »

spuz wrote: post #2

The linked article that gives the background on this mission and its recovery is definitely worth reading [0]. In particular, it's worth noting that the STEREO mission was only supposed to last until 2008 and part of the reason it was lost was due to NASA's attempts to reconfigure it to survive the unplanned period it would be out of contact from Earth as it passed behind the Sun. It would be pretty impressive if the…

    > "In 2019, the spacecraft will be far enough from the sun
    > that we could image it directly with Hubble and figure
    > out the rate of spin," said Ossing.
Nice.

Re: Nasa Establishes Contact with STEREO Mission

#16

Post by kylek »

6stringmerc wrote: post #9
spuz wrote: post #2

The linked article that gives the background on this mission and its recovery is definitely worth reading [0]. In particular, it's worth noting that the STEREO mission was only supposed to last until 2008 and part of the reason it was lost was due to NASA's attempts to reconfigure it to survive the unplanned period it would be out of contact from Earth as it passed behind the Sun. It would be pretty impressive if the…

Whoa, very cool. Waste not, want not. Well, science is kind of miss-and-hit (re: odds) so when they succeed and find additional use, that's inspirational I think. Kind of had a funny mental image of the team wrapping up the shut-down process. Then, recently, all of them still at NASA get a calendar notification from the past: "SETERO-B about to return from behind the sun - go try and jump start it!" and they get back…

The numbers on the Mars rover missions are more staggering in my opinion. From wikipedia (https://en.wikipedia.org/wiki/Mars_Exploration_Rover) :

The total cost of building, launching, landing and operating the rovers on the surface for the initial 90-sol primary mission was US$820 million.[4] Since the rovers have continued to function beyond their initial 90 sol primary mission, they have each received five mission extensions. The fifth mission extension was granted in October 2007, and ran to the end of 2009.[4][5] The total cost of the first four mission extensions was $104 million, and the fifth mission extension is expected to cost at least $20 million.[4]

Jet Propulsion Laboratory (JPL) lost contact with Spirit after last hearing from the rover on March 22, 2010 and continued attempts to regain communications lasted until May 25, 2011, bringing the elapsed mission time to 6 years 2 months 19 days, or over 25 times the original planned mission duration.[9]

Re: Nasa Establishes Contact with STEREO Mission

#17

Post by dmix »

> Mission Operations team over several hours to characterize the attitude of the spacecraft

> The STEREO Missions Operations team plans further recovery processes to assess observatory health, re-establish attitude control

Did they mean altitude? What does attitude mean?

Re: Nasa Establishes Contact with STEREO Mission

#18

Post by kerbalspacepro »

dmix wrote: post #17

> Mission Operations team over several hours to characterize the attitude of the spacecraft > The STEREO Missions Operations team plans further recovery processes to assess observatory health, re-establish attitude control Did they mean altitude? What does attitude mean?

Attitude is the orientation of a spaceship. It is where a spaceship is pointing in space relative to other things.

Re: Nasa Establishes Contact with STEREO Mission

#19

Post by mturmon »

mikeash wrote: post #11
codezero wrote: post #3

Earlier quoted context omitted.

I imagine this happens more often than most people realize. I worked on a satellite that was launched in 2003 and had a lifetime of 3 years. It operated until at least 2012 when the Air Force decided it was done paying for the downlink, but the satellite itself was still in pretty good condition.

I always assumed this happened because the official lifetime is defined in terms of some high probability of surviving that long, maybe 95%. And if you have a 95% chance of lasting 3 years, you probably have something like a 50% chance of lasting a decade or two. Is that assessment vaguely correct?

That's true ("ability to operate") but another large factor (for scientific space missions) is the demonstrable benefit to continuing -- even if the spacecraft is fully operable. For instance, New Horizons, once it flew by Pluto, had accomplished its primary science mission, and an end could have been declared at that time.

But then the NH science team put together a rationale for an "extended mission" with the new objective of visiting a Kuiper Belt Object, which was accepted by NASA.

But on the other hand, at the same time, the Dawn spacecraft's proposed extended mission to leave Ceres and visit Adeona, was denied, and it is expected to just orbit Ceres for the rest of its lifetime. (More: http://spaceflightnow.com/2016/07/02/pluto-probes-extended-m...)

So the surplus lifetime might not be used if the further science benefit can't be justified -- against engineering effort, downlink, etc. Sometimes portions of a spacecraft are turned off but the low-bandwidth observations are still taken and downlinked.

Or, sometimes a spacecraft is kept operating, with great engineering effort, even though it is not in great shape.

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