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Can Nozomi enter Mars orbit?



 
 
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  #1  
Old November 20th 03, 08:19 PM
Jim Kingdon
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Default Can Nozomi enter Mars orbit?

People have hailed the upcoming arrival at Mars of NASA's two Mars
landers, Mars Express (with Beagle 2), and Japan's Nozomi. The Nozomi
team has managed to pull off quite a few workarounds for problems
they've had. Quite impressive. But based on recent reports, I wonder
if their luck is running out. In a nutshell, here is the problem as I
understand it:

However, in late December 2003/early January 2004 the craft must fire
its onboard thrusters to enter Mars orbit. The heating system will be
required for this manuever, ISAS will be attempting to recover use of
the heating system by recycling the onboard electronics hundreds of
times to try to eliminate the short.

If the heating system is working, Nozomi will be inserted into a
highly eccentric Mars orbit
http://nssdc.gsfc.nasa.gov/database/...g?sc=1998-041A

And my question is: have they had any success in reviving the heating
system? Unless I misunderstand the reports, they've been trying since
July or so, and have not succeeded to date. Furthermore, I would
think that recycling the electronics hoping to eliminate a short would
be, well, far from assured of success.

Can any of Nozomi's instruments get useful data from a flyby only?

There has been some confused reporting in recent days about whether
Nozomi is in danger of hitting Mars. See for example
http://www.planetary.org/html/news/a..._11-14-03.html
or http://www.space.com/missionlaunches...te_031115.html .
But that isn't the real issue. In order to enter orbit, Nozomi needs
not just the ability to do a trajectory correction (which I'm not sure
is in doubt), but also needs to be able to perform a Mars insertion
burn.

Various stories: http://www.marsnews.com/missions/nozomi/

  #2  
Old November 20th 03, 08:45 PM
Chris Jones
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Default Can Nozomi enter Mars orbit?

Jim Kingdon writes:

[...]

if their luck is running out. In a nutshell, here is the problem as I
understand it:

However, in late December 2003/early January 2004 the craft must fire
its onboard thrusters to enter Mars orbit. The heating system will be
required for this manuever, ISAS will be attempting to recover use of
the heating system by recycling the onboard electronics hundreds of
times to try to eliminate the short.

If the heating system is working, Nozomi will be inserted into a
highly eccentric Mars orbit
http://nssdc.gsfc.nasa.gov/database/...g?sc=1998-041A

And my question is: have they had any success in reviving the heating
system? Unless I misunderstand the reports, they've been trying since
July or so, and have not succeeded to date. Furthermore, I would
think that recycling the electronics hoping to eliminate a short would
be, well, far from assured of success.


I agree with your summary and conclusion, and, no, they have had no
success in reviving the heating system. The hydrazine supply previously
froze and only thawed when Nozomi moved closer to the sun, and it is
thought to be frozen again as Nozomi has receded from the sun, which is
why the heating system is required.

Can any of Nozomi's instruments get useful data from a flyby only?


I don't know if they could if they were working, which they are not, and
it's not at all clear (I would say "extremely doubtful") that the
onboard power system is up to the task of powering the instruments at
this point.

The reporting on whether Nozomi is in danger (and how much danger) of
hitting Mars is, as you said, confusing. My current impression is that
the chance is not very high. I also believe that, while Nozomi's ground
controllers haven't given up hope, hope is about all they have left, and
there is no realistic chance of Nozomi either entering Martian orbit or
performing any science at Mars.

  #3  
Old November 23rd 03, 02:05 AM
Jim Kingdon
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Default Can Nozomi enter Mars orbit?

I also believe that, while Nozomi's ground controllers haven't given
up hope, hope is about all they have left, and there is no realistic
chance of Nozomi either entering Martian orbit or performing any
science at Mars.


Seems like it. Those behind Nozomi should be lauded for keeping it
going as long as they did.

Oberg has written a nice article which summarizes the situation:
http://www.msnbc.com/news/996466.asp?0cv=CB20&cp1=1

The information isn't drastically new since my post on Thursday. But
the spin is changing, and reading between the lines of
http://www.isas.ac.jp/e/snews/2003/1120.shtml (as Oberg does) gives a
pretty good idea that recovery is, well, "far from assured" would be a
generous way of putting it.

  #4  
Old November 25th 03, 12:02 AM
Jim Kingdon
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Default Can Nozomi enter Mars orbit?

A correspondent asks me whether Nozomi could be targeted to impact
Deimos or Phobos, a la Deep Impact. I don't know whether the
controllers have enough control over Nozomi or not, to hit a
relatively small target like that.

But the bigger question is whether there is anything which has
instruments which could detect anything interesting about the impact.
The Moon has/had the Apollo seismometers, Deep Impact has an orbiter
in addition to the impacter, etc. I'd be a bit surprised if Hubble,
MGS, Mars Odyssey, etc, could even detect an impact of a small
spacecraft on a Martian moon, much less measure something of
scientific interest.

  #5  
Old November 29th 03, 04:43 AM
Explorer8939
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Default Can Nozomi enter Mars orbit?

A better question is: what can Nozomi study while passing by Mars?
There should be *something* useful that the probe could do in its only
flyby.


Jim Kingdon wrote in message ...
A correspondent asks me whether Nozomi could be targeted to impact
Deimos or Phobos, a la Deep Impact. I don't know whether the
controllers have enough control over Nozomi or not, to hit a
relatively small target like that.

But the bigger question is whether there is anything which has
instruments which could detect anything interesting about the impact.
The Moon has/had the Apollo seismometers, Deep Impact has an orbiter
in addition to the impacter, etc. I'd be a bit surprised if Hubble,
MGS, Mars Odyssey, etc, could even detect an impact of a small
spacecraft on a Martian moon, much less measure something of
scientific interest.


 




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