Phoenix in Space? (APOD 27 May 2008)

neufer · Post by **neufer** » Tue May 27, 2008 3:58 pm

HiRISE Image of Phoenix descent on the parachute.
http://phoenix.lpl.arizona.edu/news.php

Why remove the Mars background?
http://apod.nasa.gov/apod/ap080527.html

-------------------------------------
Steve the Cat
http://www.stevethecat.com/mars.htm
-------------------------------------

Arramon · Post by **Arramon** » Tue May 27, 2008 5:36 pm

Isn't that just garbage from the air picked up by the camera taking the image as the landing is descending? I don't think that's actual landscape behind it. They just enhanced the detail of the lander and parachute. =/

FreebirdsWB · Post by **FreebirdsWB** » Tue May 27, 2008 6:10 pm

From everything I've read and thinking about what MRO is for, where it's cameras are pointed, etc... that IS Mars in the background. And they didn't remove it as much as change the camera's optics. It's like taking a photo with backlight on/backlight off. It is an effort to improve the contrast and see Phoenix better.

iamlucky13 · Post by **iamlucky13** » Tue May 27, 2008 7:22 pm

They didn't remove it. The picture on the Phoenix site is brightened and contrast enhanced pretty severely so that the parachute is overexposed. If you look close at the APOD, you can still see the texturing behind the lander, and even some faint details of the parachute. These are blown out in the version on the Phoenix site, although in exchange, you can see the parachute cords.

iamlucky13 · Post by **iamlucky13** » Wed May 28, 2008 12:04 am

Holy cow! I just about fell out of my chair when I saw this (neufer, here's your definitive answer):

http://hirise.lpl.arizona.edu/phoenix-descent.php

Note, it's not falling into the crater. Foreshortening from the long focal length of HiRISE skews the perspective. From the HiRISE site:

"Although it appears that Phoenix is descending into the crater, it is actually about 20 kilometers in front of the crater. It is difficult to believe that it is in front of the crater because it is so much smaller, but in reality it is, and that's a good thing because landing on the steep rocky slopes of the crater would have been far too exciting (or risky)."

I've never even seen a picture of the space shuttle like these, and we've had a 100+ opportunities to take such photos from who knows how many satellites. NASA just blew my socks off.

MRO also caught a picture 22 hours after landing:
http://hirise.lpl.arizona.edu/phoenix-hardware.php

astrolabe · Post by **astrolabe** » Wed May 28, 2008 1:44 am

Hi All,

Are those little black things in the soil around the landing foot....BUGS?

All kidding aside I can hardly express my elation over this episode of Earth's history. I'm certainly not trivializing any previous failures or successes; the valuable knowledge gained served future missions very well indeed.

Now, two questions:
1) Is the Phoenix an immobil science platform?
and 2) Would the thrusters used in the soft landing have interfered
with the ICE in the soil and maybe sterilized the scoop area?

I guess that was the point of my first question.

BMAONE23 · Post by **BMAONE23** » Wed May 28, 2008 5:42 am

answer to 1...yes it is a stationary platform and can only reach with its scoop over a relatively small area.
as for 2???? I wondered about that myself, especially since the area around the lander appears to be darkened from the thrusters.

http://hirise.lpl.arizona.edu/images/20 ... _cut_e.jpg

http://hirise.lpl.arizona.edu/phoenix-hardware.php

zbvhs · Post by **zbvhs** » Wed May 28, 2008 11:17 am

Fantastic pictures. The vehicle was apparently caught early in the parachute phase of the descent as the parachute is still reefed prior to opening completely. That the shroud lines are visible is simply amazing.

The vehicle was probably at a fairly high altitude at the time and still had some distance yet to travel downrange before landing.

Dr. Skeptic · Post by **Dr. Skeptic** » Wed May 28, 2008 11:49 am

BMAONE23 wrote:answer to 1...yes it is a stationary platform and can only reach with its scoop over a relatively small area.
as for 2???? I wondered about that myself, especially since the area around the lander appears to be darkened from the thrusters.

http://hirise.lpl.arizona.edu/images/20 ... _cut_e.jpg

http://hirise.lpl.arizona.edu/phoenix-hardware.php

Phoenix's "Scoop Arm" can reach about 2 meters, the hydrazine propellant decomposes exothermically into hydrogen, nitrogen and ammonia, the arm's reach should be able to avoid any residual thruster disruption or fuel contamination.

henk21cm · Post by **henk21cm** » Wed May 28, 2008 12:36 pm

BMAONE23 wrote:I wondered about that myself, especially since the area around the lander appears to be darkened from the thrusters.

If any disturbance has occured, it will be superficial. Soil -especially dry soil- is known to have a poor heat conductivity, so if the soil is heated up, just a few centimeters deep it will be virtually undisturbed. So if Phoenix is ably to digg a few cm deep, distubance by exhaust gasses is a minor problem. Additionally, hot gasses have a tendency to rise, even in the thin Martian atmosphere, not in the least cooling will have occured by induced turbulence and entrainment, when Martian atmosphere is mixed with burned 'fuel' gasses.

The only scenario which may have caused seroius damage is, when the lander is already sound and fixed at the surface, while the engines are still working. It may be an urban myth, when Apollo11 landed on the moon, it was told that the engines were shut down a few meters above the Lunar surface, in order to prevent too much dust. "Forward, forward, picking up dust, forward. Engines stopped, Tranquility base, the Eagle has landed" or words of similar meaning and rearrangement.

Arramon · Post by **Arramon** » Wed May 28, 2008 5:18 pm

So if Phoenix is ably to digg a few cm deep, distubance by exhaust gasses is a minor problem.

ugh... gotta get that digg link out of here! its corrupting the minds of all...

=b

neufer · Post by **neufer** » Thu May 29, 2008 2:23 am

iamlucky13 wrote:http://hirise.lpl.arizona.edu/phoenix-descent.php

Note, it's not falling into the crater. Foreshortening from the long focal length of HiRISE skews the perspective. From the HiRISE site:

"Although it appears that Phoenix is descending into the crater, it is actually about 20 kilometers in front of the crater. It is difficult to believe that it is in front of the crater because it is so much smaller, but in reality it is, and that's a good thing because landing on the steep rocky slopes of the crater would have been far too exciting (or risky)."

http://en.wikipedia.org/wiki/Heimdall_% ... _crater%29
http://en.wikipedia.org/wiki/Heimdall

<<Heimdall (Old Norse Heimdallr, the prefix Heim- means home, the affix -dallr is of uncertain origin) is one of the Æsir (gods) in Norse mythology. Heimdall is the guardian of the gods and of the link between Midgard and Asgard, the Bifrost Bridge. Legends foretell that he will sound the Gjallarhorn, alerting the Æsir to the onset of Ragnarök where the world ends and is reborn. Heimdall is described as being so alert that he requires no sleep at all. He can hear the grass grow and see to the end of the world; he can hear a leaf fall. Heimdall is described as a son of Odin, perhaps a foster son. Heimdall was destined to be the last of the gods to perish at Ragnarök when he and Loki would slay one another.>>

Nerull · Post by **Nerull** » Thu May 29, 2008 2:17 pm

Get out a camera, and find a darkish setting. Put a really bright object in that setting, and take a short exposure.

Wow, everything around the object is really dark! You must be in space!

Or you just need to realize how cameras work.

Arramon · Post by **Arramon** » Fri May 30, 2008 5:31 pm

Dark room, mirror, camera phone with flash. Take a picture of the flash reflection in the mirror and you will get two white objects seemingly floating in black space that is similar to a solar object with a small body reflecting the larger object's light.

Easy enough.

Starship Asterisk*

Phoenix in Space? (APOD 27 May 2008)

Phoenix in Space? (APOD 27 May 2008)

HiRISE Heimdall: guardian of the Bifrost Bridge