New Horizons flyby of Pluto [updated for Ultima Thule]

[rootone]

Into July.
Now only two weeks to wait for the real thing ... !
http://www.nasa.gov/mission_pages/newhorizons/main/index.html

 

[D H]

Into July.
Now only two weeks to wait for the real thing ... !
http://www.nasa.gov/mission_pages/newhorizons/main/index.html

Word of warning: Do not expect a lot from this mission, at least not at first. There will be a few last pre-flyby images sent on July 13, the day prior to the flying. On the day of the flyby, nothing. New Horizons will be looking at the Pluto/Charon system during the flyby, not at the Earth. It can't do both. There will be a "phone home" signal sent to Earth after the flyby, but this will just contain system telemetry data. The vehicle will send a few highly compressed "first look" and "high priority" images Earthward in the days that follow the flyby, and then nothing. Image transmission will cease on July 20th and won't resume until mid September. That's when we'll slowly start seeing the good stuff.

 

[rootone]

What is the reason for the pause until September before the bulk of data gets transmitted?
I know these breaks in transmission occur with the Mars rovers because the Sun gets in the way.

 

[D H]

What is the reason for the pause until September before the bulk of data gets transmitted?
I know these breaks in transmission occur with the Mars rovers because the Sun gets in the way.

It's not the Sun. Pluto will be in opposition on July 6, just a week before the flyby.

New Horizons will not send any data Earthward during the flyby. New Horizons doesn't have a scan platform or a pointable antenna. To talk with the Earth, the entire vehicle has to slew so as the have the antenna pointing toward the Earth. To see Pluto, the entire vehicle has to slew so as to have the science package pointing toward Pluto. Communication and science are in direct conflict on the day of the flyby. Collecting scientific data wins; collecting as much data as possible during the flying is the sole reason this mission exists. Data collected on the way to Pluto was an extra bonus, as will be any data collected from a future encounter with some other trans-Neptunian object.

Another point to remember: The data transmission rate from New Horizons is rather low. It has to be due to the distance to Pluto. By design, New Horizons records data and transmits it to Earth at some later time. It will take well over a year to transmit the recorded flyby data to Earth.

I haven't found out why this gap exists; I can only hazard guesses. Once is a much reduced urgency once the flyby is over. Pre-flyby data, including imagery used for visual navigation, were used to keep the flyby on target. Post-flyby, what's happened has already happened. Another possibility is that New Horizons will collect non-imagery data. Perhaps this non-imagery data is what will be transmitted during that two month lull. (I don't know if this is the case.) Yet another possibility: The team has to be in desperate need of a vacation.

 

[Imager]

Anyone have info on the problems with New Horizon's computer?

From the article:

On Saturday, an unknown glitch caused New Horizons to switch to a backup computer, which triggered an 81-minute break in radio communications with mission controllers at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, NASA said in a status report.

"Full recovery is expected to take from one to several days," NASA said. "New Horizons will be temporarily unable to collect science data during that time."​

http://www.reuters.com/article/2015/07/05/us-space-pluto-idUSKCN0PF0HW20150705

 

[Drakkith]

Anyone have info on the problems with New Horizon's computer?

From the article:

On Saturday, an unknown glitch caused New Horizons to switch to a backup computer, which triggered an 81-minute break in radio communications with mission controllers at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, NASA said in a status report.

"Full recovery is expected to take from one to several days," NASA said. "New Horizons will be temporarily unable to collect science data during that time."​

http://www.reuters.com/article/2015/07/05/us-space-pluto-idUSKCN0PF0HW20150705

Gah! No no no! Hang in there, little buddy! Hang in there!

 

[Imager]

The main computer on the New Horizons probe is back up and running!

From NASA

The investigation into the anomaly that caused New Horizons to enter safe mode on July 4 has confirmed that the main computer was overloaded due to a timing conflict in the spacecraft command sequence. The computer was tasked with receiving a large command load at the same time it was engaged in compressing previous science data. The main computer responded precisely as it was programmed to do, by entering safe mode and switching to the backup computer.

Thirty observations were lost during the three-day recovery period, representing less than one percent of the total science that the New Horizons team hoped to collect between July 4 and July 16. None of the mission’s most critical observations were affected. There’s no risk that this kind of anomaly could happen again before flyby, as no similar operations are planned for the remainder of the Pluto encounter.​

https://www.nasa.gov/feature/nasa-s-new-horizons-on-track-for-pluto-flyby

 

[nsaspook]

I would hope there is a 'battle short' mode during the critical data flyby mission.

 

[Lord Crc]

If I recall correctly the Deep Space Network, which is used for communicating with the probe, is quite taxed. Maybe some other projects got priority. As mentioned, there's no huge rush.

 

[davenn]

If I recall correctly the Deep Space Network, which is used for communicating with the probe, is quite taxed. Maybe some other projects got priority. As mentioned, there's no huge rush.

did you not read the NASA quote in post #7 ?
the problem wasn't with the DSN

 

[Lord Crc]

did you not read the NASA quote in post #7 ?
the problem wasn't with the DSN

I meant to reply to post #4, about the delay until September for the data return. Quoting is so awkward in the mobile interface and I forgot to specify due to sleepy brain.

 

[Drakkith]

I meant to reply to post #4, about the delay until September for the data return. Quoting is so awkward in the mobile interface and I forgot to specify due to sleepy brain.

Are you using the PF Mobile App, or just your phone's browser? If you aren't using the PF App, I recommend it over the tiny browser buttons and such.

 

[Janus]

Imagine the surprise if some "unusual" geographic features came to light.

 

[Drakkith]

Where's that image from, Janus?

 

[Janus]

Where's that image from, Janus?

It's my own creation.

 

[Drakkith]

Omg I JUST realize what the terrain was. Pluto on Pluto!

 

[Dotini]

What do you suppose the chances are for indications of recent activity on the surface of Pluto? I'm optimistic.

 

[Drakkith]

What kind of recent activity?

 

[Dotini]

What kind of recent activity?

Not Mickey and Pluto running around!
I'm hoping to see some atmospheric or geologic activity due to energy imparted by Pluto's dynamic elliptical orbit and/or its close family of moons.

 

[DaveC426913]

What kind of recent activity?

Impact crater from a sleeping probe?

 

[B1948J]

OK, here is the latest photo from New Horizons as published by Popular Science. Their article claims this photo was taken from a distance of 3.7 miles. Intuitively this seems way off. The known distance between Charon and Pluto is 12,200 miles. Pluto's diameter is 1,471 miles. I've been trying to figure out how to calculate the actual distance from the camera to Pluto using trig but can only come up with one side and no angles using only the photo. Can anyone help me prove or disprove the purported distance?

 

[mfb]

3.7 million miles would be realistic.
The current distance is 4.6 million km (2.9 million miles).

 

[B1948J]

3.7 million miles would be realistic.
The current distance is 4.6 million km (2.9 million miles).

Thank you! Do you have any idea of how one might calculate this based on the photo?

 

[mfb]

Not without more information about the camera, like its angular resolution.

Actually... you could determine when this picture has been taken based on the apparent distance of Pluto and Charon and the trajectory of the two objects and New Horizons, and use this to determine the distance. That sounds quite complicated and you have to look up the trajectories.

 

[nsaspook]

Raw image link: http://pluto.jhuapl.edu/soc/Pluto-Encounter/index.php

 

[DaveC426913]

Man, I can't believe we're seeing the actual surface of Pluto. I have been looking at "artist's impression"s of Pluto in textbooks for more than 4 decades, and now here we are.

 

[Drakkith]

Not without more information about the camera, like its angular resolution.

Actually... you could determine when this picture has been taken based on the apparent distance of Pluto and Charon and the trajectory of the two objects and New Horizons, and use this to determine the distance. That sounds quite complicated and you have to look up the trajectories.

Specs for LORRI, the imaging device that took the image: http://web.archive.org/web/20100808073101/http://www.boulder.swri.edu/pkb/ssr/ssr-lorri.pdf

The camera sensor has a 1024 x 1024 array of square pixels that are 13 microns on each side, with a resolution of about 1 arcsecond.
The optical system has an aperture of 208 mm, a focal length is 2630 mm, and a field of view of 0.29 x 0.29 degrees, or 1044 x 1044 arcseconds (1.02 arcsec per pixel).

 

[Imager]

@B1948J

Looks like this is the original article from the New Horizons website:

http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150709

View attachment 85752

OK, here is the latest photo from New Horizons as published by Popular Science. Their article claims this photo was taken from a distance of 3.7 miles. Intuitively this seems way off. The known distance between Charon and Pluto is 12,200 miles. Pluto's diameter is 1,471 miles. I've been trying to figure out how to calculate the actual distance from the camera to Pluto using trig but can only come up with one side and no angles using only the photo. Can anyone help me prove or disprove the purported distance?

 

[Drakkith]

New photos!
From here: http://www.nasa.gov/feature/new-image-of-pluto-houston-we-have-geology

 

[B1948J]

@B1948J

Looks like this is the original article from the New Horizons website:

http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150709

Thank you. I should have checked this website first.

It seemed intuitive to me that there must be some way to approximate the distance from which the photo was taken using known distances between Pluto and Charon and their diameters. It was a good mental exercise to understand why that's not so thanks to mb and Drakkith.