ICE / ISEE-3, First comet encounter September 1985 Options

[mcaplinger]

The ISEE-3 Reboot Project is pleased to announce that our team has established two-way communication with the ISEE-3 spacecraft and has begun commanding it to perform specific functions... A much more detailed description of our First Contact efforts and future plans will be published on our website next week.

Good news, but I wish they said exactly what they have done. Sending command bits and getting a change in the spacecraft state would be more encouraging than sending an unmodulated uplink carrier and getting transponding, but both could plausibly be called "two-way communication."

[gpurcell]

Is receiving telemetry the same as getting transponding?

[mcaplinger]

Is receiving telemetry the same as getting transponding?

No; transponding is just getting a phase-coherent copy of the uplink carrier back on the downlink without modulation. But based on the last updates to http://spacecollege.org/isee3/ they have succeeded in commanding the s/c to send modulated data. Still not clear what if anything is being sent, but this is definitely very encouraging.

[ElkGroveDan]

It's good news, but the people handling the PR and social media are behaving like rank amateurs. The hype at this point that the ICE / ISEE-3 team are churning out is really premature and they are setting themselves up for a media feeding frenzy if everything doesn't go exactly as planned. I get the sense that there are one or more huge egos driving this rather than the cooler heads we typically encounter with NASA professionals.

[mcaplinger]

they are setting themselves up for a media feeding frenzy if everything doesn't go exactly as planned.

On the contrary, my sense is that the media loves the underdog spin and even if they don't do anything else they'll be viewed as heroes for having tried on their "shoestring budget."

I can appreciate that the tone of what they write is a bit grating, but I propose we treat them with rule 2.6 in mind as much as possible.

[bobik]

Could anyone please explain this statement to me? It sounds like a paradox: We have successfully commanded both of ISEE-3's data multiplexers into engineering telemetry mode. The current bitrate is 512 bits/sec. … When we are confident of the state of the spacecraft, we will be placing the bird in engineering telemetry mode as soon as possible.

[mcaplinger]

Either it's poorly worded and the spacecraft is already in engineering mode, or it's possible to set the multiplexers to produce a modulated data stream but not pull actual data from sources on the spacecraft. In the latter case one presumes the data being sent would be fill or garbage. I haven't found any information that describes the ISEE systems in enough detail to know for sure. http://nssdc.gsfc.nasa.gov/nmc/spacecraftT...do?id=1978-079A has a little but not much.

[stevesliva]

It's good news, but the people handling the PR and social media are behaving like rank amateurs. The hype at this point that the ICE / ISEE-3 team are churning out is really premature and they are setting themselves up for a media feeding frenzy if everything doesn't go exactly as planned.

I disagree. It's all in good fun, and I actually don't think there's too many chance of headlines like "$15 million** NASA probe DIES," because hey, even the media can figure out this thing's old. There's really no downside. (** Or whatever... what did this thing cost to make in the mid-70s?)

*My* cynicism is... there's probably not much practical reason to do any of this. But I still think it's neat.

[nprev]

I just hope that they don't try any truly absurd grandstanding. That ridiculous statement about ISEE-3 possibly colliding with Earth-orbiting sats still really sticks in my craw.

The right thing to do here would be to use this exercise as an EPO tool to inform people about the very interesting & too often unappreciated field of spacecraft command & control. I'd honestly love to read a book about their efforts when it's all over. But if they or some individual(s) among them try to portray their efforts as anything but doing something very cool for the sheer fun of it that'll definitely cross a line.

[Paolo]

as this Sky & Telescope article reminds

Once safely in near-Earth storage, ISEE 3 could easily be redirected to encounter a third comet. Although it carries no cameras, this spinning drum-shaped spacecraft has a robust set of instruments for studying charged particles, electromagnetic fields, and related phenomena.

[djellison]

At last a nice blog post full of details about exactly what they've managed to do so far!

http://spacecollege.org/isee3/isee-3-reboo...e-and-more.html

Looks like they'll need only 5.8m/sec to divert onto the appropriate lunar flyby trajectory.

[nprev]

Hats off to them! Fascinating work, and remarkable that the trajectory of the spacecraft remained so stable!

[stevesliva]

Looks like they'll need only 5.8m/sec to divert onto the appropriate lunar flyby trajectory.

If they do the TCM by June 17.

I hope they nail it!

[climber]

More news from the source pointed out by Doug.
>ISEE-3 Mission Status 3 June 2014
Telemetry we have received from ISEE-3 shows that it is spinning at 19.16 rpm. The mission specification is 19.75 +/- 0.2 rpm. We have also learned that the spacecraft's attitude relative to the ecliptic is 90.71 degrees - the specification is 90 +/- 1.5 degrees. In addition, we are now receiving information from the spacecraft'smagnetometer.

[stevesliva]

For those who were wondering what the small body radar images mentioned in an ISEE update were, here they are:
http://www.usra.edu/news/pr/2014/comet209PLINEAR/

Fairly fitting that it's a comet.