Phoenix Attempts Mars Landing TODAY!

[Greg]

Phoenix will extend its legs before it lets go of its parachute.



NASA's Phoenix spacecraft will attempt to land on Mars shortly before 8:00 PM EDT TODAY!
That's just under 7 hours from now!

Unlike the last two Mars landers, which bounced around in air bags, Phoenix will attempt a precision powered landing.

The event will be Podcast, webcast, and (I assume) carried on NASA TV and (most likely) Fox News.

See the Phoenix section of the NASA web site for more!

[Greg]

30 minutes to touchdown!

[Greg]

Touchdown! Phoenix has landed on Mars!

[Sita]

WOOT WOOT

[rdanner3]

Personally, I thought the Phoenix landed at a somewhat higher speed than I thought was safe. Apparently it did indeed touch down safely, which is very good indeed.

[Greg]

How would you know, Raymond? I didn't hear anything about the touchdown velocity other than what was in the flight plan.

[rdanner3]

Originally Posted by Greg

How would you know, Raymond? I didn't hear anything about the touchdown velocity other than what was in the flight plan.

From the countdown of the descent rate during the last five reports (prior to the landing announcement being repeated excitedly several times) it sure sounded like it landed at several meters per second, which had to be a pretty hard "soft" landing. Of course, since you've seen the flight plan, you likely know more than I do. Unlike you, I'm not a rocket scientist, though I was a pretty avid hobbyist (flying-model) rocketeer when I was younger. (Still want to try flying my most ambitious project, since I think it'd go pretty high, perhaps requiring a NOTAM. Built the second and third stages, then lost both to a series of quick moves (6 in just over 2 years, and I'm not military) so still don't know if the thing could survive the intense thrust to weight ratios that were working up. (second and third stages, mated together, were absolutely stable in tests with lesser engines, as was the third stage on its own. First stage was causing me heartburn trying to build it with enough support for the four-engine mount, though. At 4 pounds of thrust each, F100 engines aren't easy to build mounts for out of what most hobbyists have available.))

May rebuild the design fully one of these days. Problem is, it will require assistance to track and recover, I expect, especially if I've properly calculated the apogee altitude (in excess of 11,000 feet) and there's significant upper-level winds the day of the launch! LOL (estimated thrust to weight of the first stage is a whopping 3.5:1. Third stage is close to 4:1. The thing is seriously overpowered, but the weights I'm basing those T:W ratios on might be off, too. Could be even more powerful, unless I reduce it to 6 engines (3 in first stage, 2 in the second, 1 in the third) from the original plan's eight. (4 in the first, 3 in the second, 1 in the third)

[mikedelaney16]

It took several seconds to drop that last 15 meters, I'm only guessing, but I'd say about 3 seconds. That would equate to about 5 meters per second or a mere 10 miles per hour. Personally I think that qualifies as a soft landing, and if you know anyone who used to be a paratrooper he'd more than likely agree with me :-)

[Greg]

Spot on, Mike. The planned landing speed was 5 meters per second. I don't know why they didn't try for something close to zero, but that's how they designed it.

[mikedelaney16]

Originally Posted by Greg

I don't know why they didn't try for something close to zero, but that's how they designed it.

No need to try for close to zero since a man can survive a landing at 5.5 to 6.5 meters per second and still fight a battle.

[Greg]

Or in this case, with the legs to absorb the shock, the robot aboard Phoenix and survive the landing.

I missed the news conference when it came on NASA TV this afternoon, darn it. As best I can tell from the web site, they won't run it again until 2:00 PM EDT tomorrow. Rats.

[Hokieman]

I read something today about one of the arms didn't jetison it's protective covering and they were going to try to extend it later today.

[Greg]

Yeah, I saw that but I can't say that I understood it. The impression I got is that they'll have to fiddle with it for another day before they can full extend the arm. Maybe htey have some way to dislodge the protective cover.

It's interesting to think that this is only the sixth robotic probe that has landed on Mars after all these years.

[Hokieman]

Ok, it's obvious that I'm not keeping up on Mars (or space, in general) exploration. I thought it was just the 2nd.

[Greg]

Let's see... the ones I was thinking of are:

1. Viking 1 (launch 1975)
2. Viking 2 (launch 1975)
3. Pathfinder (launch 1996)
4. Spirit (launch 2003)
5. Opportunity (launch 2003)
6. Phoenix (launch 2007)

The Viking missions were lots of fun. They had planned on a 90-mission after landing on the surface, but Viking 2 lasted until 1980 and Viking 1 kept transmitting until November 11, 1982!

Next will be the Mars Science Laboratory, scheduled for launch in Autumn 2009.

[Hokieman]

Thanks, for some reason I thought the Viking missions were flybys, not landings. And I didn't realize there were 2 missions launched in 2003.

[Greg]

Yup. It was the Vikings that gave us our first pictures of the surface Mars with its salmon-colored sky.


Viking 1's first day on Mars


I remember it well. Back in 1976, I was at the World Science Fiction Convention in Kansas City when Jerry Pournelle came in with slides from the first pictures that came up at JPL. The first images they released had been color corrected to show a blue sky, but once someone checked the color reference on Viking's leg, they realized the error and immediately released a new version with the correct color.


Then, just a while later in 2004, the roving robots "Spirit" and "Opportunity" landed on opposite sides of the planet. By then the folks at JPL had learned to play up the publicity and give cute names to everything, even the rocks that the robots visited.

[Miros1]

Actually, the robots are usually referred to as "Spirit and Opportunity" in the media, so that's probably why Hokieman thought they'd been launched together. Are they still going, or did dust and whatnot finally run them into the ground?

[Greg]

On the JPL site they're still identified as "current" missions so I would guess that means they're still going.

With the recent successes they have had with rovers, I'm kind of surprised that Phoenix doesn't have tracks on it. It was probably a trade-off against the extra weight.

[Hokieman]

Thanks Greg.

I seem to remember them having intermittant comm problems on at least one of the 2003 robots, and they eventually lost contact.

Rose nailed it, I thought the 2003 missions were one with redundant rovers.