Ask Team Trying To Return 36-Year-Old Spacecraft From Space About Their Project

samzenpus (5) writes "Last week we told you about a group that was trying to recover the 36-year-old ISEE-3 spacecraft from deep space. Led by CEO and founder of Skycorp, Dennis Wingo, and astrobiologist and editor of NASA Watch, Keith Cowing, the crowdfunded project plans to steer ISEE-3 back into an Earth orbit and return it to scientific operations. Once in orbit, they hope to turn the spacecraft and its instruments over to the public by creating an app that allows anyone access to its data. The team has agreed to take some time from lassoing spacecraft from deep space in order to answer your questions. As usual, ask as many as you'd like, but please, one question per post. Hopefully the plan goes better than xkcd predicts."

Why wouldn't you focus on more productive things?

[Anonymous Coward]

Seriously ... this spaceship wasn't intended for a museum. It served its purpose and you are demeaning it by attempting to retrieve it. WTF? Why are we launching things if we're just going to try to get them back? We're better off not launching them to start with. We are best served focusing our efforts towards further exploration - looking forwards, not backwards.

Public Data Access

[jshahbazi]

If the project is successful, how do you envision the public being able to access the data from the satellite? Will it be a stream of everything, or will only selected instruments be available?

How do we know this will even work?

[Anonymous Coward]

Another question I have is this: How do you know this project will even work? The XKCD comic claims that NASA sent a shutdown signal to ISEE-3 in 1998, which apparently was either not received or not properly executed. Is there any way of telling whether or not the control communications to the satellite even work anymore? What happens to the crowdfunding money if it is discovered that the comms equipment doesn't work, or that it's simply not feasible to build a system to emulate the original hardware controls in time to bring the satellite into Earth orbit?

What is the value?

[bengoerz]

Other than the sentimentality, what are the real benefit of bringing ISEE-3 home? If the benefit is the data, what is the evidence that the "data that ISEE-3 could generate would have real value"? If the benefit is educational, which institutions have committed to taking part?

Re:How do we know this will even work?

[Anonymous Coward]

Hi this is Dennis Wingo, co project manager of the ISEE-3 Reboot project.

We already know that the spacecraft's two transponders are transmitting. This gives a very good indication that the power budget is positive. We also know, by looking just at the received signal that the spacecraft is still spinning at about the same rate as in 1999. We also know that the last time the spacecraft was contacted, that the vast majority of the instruments were still functional. The spacecraft is in a very stable orbit from a thermodynamics perspective, meaning that with a benign thermal environment and a positive power margin there is every chance the the spacecraft is still fully functional. Our next test is of the receivers on the spacecraft, and that will happen sometime in late May, depending on some data that we are waiting on from NASA.

We also have the example of the two voyager spacecraft which are from the same era, with a lot of comparable hardware, that is still functioning. We have found documents with the degradation curve of the power system solar cells and we still have a good power margin for the instruments.

Also, and this is a bit of an update. We are already in process of procuring the transmitter and it will be delivered to our ground station in time for a contact. We have a team that has already done a lot of the work to redevelop the modem, the modulator/demodulator pair for the satellite. This is being done with software radio. The good part about this is that the modulation scheme and demodulation scheme on the spacecraft is primitive in comparison to today, and thus is easy to develop.

We also have a team redeveloping the telemetry monitors for the propulsion system the attitude determination and control system, and the power system. The team is already simulating that.

We also have far advanced orbital dynamics software, principally Satellite Tool Kit, from Analytical Graphics. That software will be used to refine the calculations for the engine burns to validate the hand calculations from Dr. Farquhar and Dave Dumham, the two scientists and engineers that did these calculations for all the previous course changes.

We have a great team for commanding the spacecraft, Tim Reyes, who has experience in this domain, as well as others that are coming on board now.

It is feasible and indeed is in progress to get this spacecraft evaluated.

The biggest issue will be updating the ephemeris of the spacecraft to refine its position for the orbit correction burn. That is a big dragon to slay but we are working that problem.