[meteorite-list] NASA Phoenix Lander Bakes Sample, Arm Digs Deeper

From: lebofsky at lpl.arizona.edu <lebofsky_at_meteoritecentral.com>
Date: Wed, 18 Jun 2008 03:37:00 -0700 (MST)
Message-ID: <51384.71.226.60.25.1213785420.squirrel_at_timber.lpl.arizona.edu>

Hello Sterling:

I think that it was a software failure that doomed Mars Polar Lander:

When the spacecraft sensed that the vehicle had landed, then the engines
were to cut off. This was done by noting that the landing legs flexed
(sprung back as a shock absorber) as the ship touched down.

However, as it turned out, when the legs were deployed, having springs,
guess what, they sprung back a little. The engines sensed this as "we are
on the ground" and not "oh, the legs just deployed," and so the engines
turned off at 40 meters altitude, making the landing not so soft.

Larry

On Tue, June 17, 2008 11:51 pm, Sterling K. Webb wrote:
> Hi, Pete, List,
>
>
> This mission was named Phoenix in recognition
> of the fact that like the mythical Phoenix, it rose from the ashes of the
> dead! Once upon a time, there were two Mars missions that died: the 2001
> Mars Surveyor
> lander was cancelled in 2000, and the Mars Polar Lander was lost on Mars in
> 1999.
>
>
> Demonstrating the inscrutable wisdom that politicians,
> beaurocrats, and authorities often possess that we lowly groundlings lack,
> the 2001 Mars Surveyor Lander was canceled after it was already built and
> paid for. (Anybody remember the Superconducting Super Collider?)
>
> At any rate, the 2001 Mars Surveyor Lander had been
> kept in storage at Lockheed Martin clean room in Sunnyvale. And there were
> extra "stay-at-home" duplicates of some instruments for the Polar Lander,
> and there was a bit here and there, and there were projects without a
> vehicle or hope of getting another one...
>
> Upshot: for a lousy $386 million, which includes the launch
> and all tips for room service, You The Taxpayer get a whole new Mars
> Mission. Quit whining. For comparison, we spend
> $343 million each and every day in Iraq doing whatever it is
> that we're doing there.
>
> Actually, I lied. Phoenix needed an extra $31 million beyond
> the budget of $386 million and was almost cancelled over it. The altimeter
> was from the Mars Polar Lander (you know, the one that crashed). It seems
> that, hmm... a faulty altimeter may have been to blame for that.
>
> It's taken from the one used in F-16 fighter planes. Some
> software problems on the F-16 altimeter were fixed, but the altimeter for
> Phoenix did not get the software upgrade. They
> spent about six months fixing the gizmo, driving up costs. And, hey! It
> worked, didn't it?
>
> Additionally, they had to pay for searching for a boulder-free
> landing spot, using the Mars Reconnaissance Orbiter which, yes, charges for
> its services, even to other missions, because every spot they picked had
> boulders. There's a helluva lot of boulders on Mars...
>
> <quote> The partnership developing the Phoenix mission
> includes: the University of Arizona, NASA's Jet Propulsion
> Laboratory, Lockheed Martin Space Systems in Denver and
> the Canadian Space Agency, which is providing weather instruments. Peter H.
> Smith of the University of Arizona, Lunar
> and Planetary Laboratory heads the Phoenix mission. <unquote>
>
> Thanks.
>
>
> Born from the ashes it may be, but Phoenix will die in the cold.
> It's going into summer in the Martian Arctic; the mission lifetime is
> about 150 days. Phoenix won't survive winter.
>
> I also notice news people describing the Phoenix as having
> landed at Mars's "North Pole," even people on this List. If you were aliens
> going to land on Earth, would you land on the dead center of Antarctica?
> Why?
>
>
> Phoenix is on the southern edge of the "Boreal Vastness"
> (translating from the Latin name); it is above the Martian Arctic
> Circle, barely (68.35 deg North). For a location comparison
> by latitude, think of landing in the Northwest Territories of Canada. The
> "Boreal Vastness" is a flat featureless low-lying
> that covers about the upper third of Mars; many think it is an ancient sea
> bed.
>
> Your criticisms might be to the point if we belonged to a
> species and lived in a culture that made rational and intelligent long-term
> plans to do the things that are truly essential and important to them.
>
> If you know of such a place, let me know.
>
>
> I sincerely hope you can convince somebody to land a
> multi-ton rompin' rover with nuclear eight-wheel drive, power take-off
> drills on both ends, linear laboratory analysis machines with continuous
> pass-through of Martian samples and 18 experiments online in each one
> (let's have four of'em) and
> a sample return rocket that sends 100 kg of Martian samples up to Martian
> orbit to be returned to Earth.
>
> Let's have two, if you're in the mood...
>
>
>
> Sterling K. Webb
> --------------------------------------------------------------------------
>
Received on Wed 18 Jun 2008 06:37:00 AM PDT