[meteorite-list] Cornell Researchers Turn To Telemetry And Geometry To Capture Distant Asteroid

From: Michael Casper <Michael_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:06 2004
Message-ID: <000a01c08fe7$37e75a20$0300a8c0_at_Domain>

This is all happening down the street from here.

  oxox, MC


----- Original Message -----
From: Ron Baalke <baalke_at_zagami.jpl.nasa.gov>
To: Meteorite Mailing List <meteorite-list_at_meteoritecentral.com>
Sent: Monday, February 05, 2001 5:43 PM
Subject: [meteorite-list] Cornell Researchers Turn To Telemetry And Geometry
To Capture Distant Asteroid


>
>
> http://www.news.cornell.edu/releases/Feb01/NEAR.control.bpf.html
>
> Images from outer space: Cornell researchers turn to telemetry and
geometry
> to capture distant asteroid
>
> FOR RELEASE: Feb. 5, 2001
>
> Cornell University News Service
> Contact: Blaine P. Friedlander, Jr.
> Office: 607-255-3290
> E-mail: bpf2_at_cornell.edu
>
> ITHACA, N.Y. -- Will this be the gang that could shoot straight? For the
> past year, engineers and computer programmers from Johns Hopkins
> University's Applied Physics Laboratory (APL), assisted by NASA's Jet
> Propulsion Laboratory (JPL) and the imaging team at Cornell University,
> have been figuring out how to slew a spacecraft precisely and aim its
> camera perfectly for the final act of its mission: alighting on an
asteroid.
>
> On Feb. 12 the Near Earth Asteroid Rendezvous spacecraft, known as NEAR
> Shoemaker, will attempt to land on Eros, an Earth-crossing asteroid about
> 196 million miles from Earth. In mid-descent, an onboard camera will
point
> toward the surface and hopefully send back the best images ever from a
> small, solar-system body. The navigational prowess of APL and JPL will be
> complemented by the imaging expertise of the Cornell research team.
>
> "It's not like this craft is landing on a sphere. It's descending on a
> potato-shaped rock that is 22 miles long, and the rock has a large,
> saddle-shaped hole on one side. The rock continuously spins end-over-end.
> Geometry is forcing us to land there -- where there is more motion than at
> the poles -- so that NEAR's solar panels face the sun, its antenna points
> to Earth and its camera faces the asteroid," says Cornell space sciences
> researcher Ann Harch. "Other than that, it's easy."
>
> Use of the navigation team's telemetry, geometry and other calculations --
> for this never-before-attempted maneuver -- required unique software to
> point the camera, and it took more than a year to perfect. Harch and her
> Cornell research colleagues Maureen Bell and Colin Peterson and programmer
> Brian Carcich worked with APL (which built the spacecraft and is managing
> the mission) to develop special computer software that, with great
> precision, displays the shape of Eros and how it will look from the
> camera's point of view. First an exact model of the asteroid's shape had
> to be determined. This shape-model software, called POINTS, developed by
> Cornell's Jonathan Joseph, programmer analyst, and Peter Thomas, senior
> research associate, correlates feature in thousands of images and plots
the
> asteroid's trajectory and orientation. From that information, the program
> calculates a detailed three-dimensional asteroid model.
>
> Harch, Bell and Peterson then used Orbit, a computer program developed at
> Cornell by Carcich, to design pointing commands for the multispectral
> imaging camera. Orbit reads input data on the asteroid's location and
spin
> orientation, then shows where the craft and camera will point. The
program
> also displays how the asteroid will look to the camera at each instant.
>
> This information allowed Harch, Bell and Peterson to cobble together
> command sequences that were uploaded to NEAR Shoemaker throughout the
> mission. The comands take about 17 minutes for the information to be
> received by the distant spacecraft and the same amount of time for the
> craft to send back confirmation that the data was received.
>
> If all goes as planned, at 10:31 a.m. Eastern time on Feb. 12, the
> spacecraft will commence firing a series of burns -- firing thrusters away
> from the asteroid -- to brake the craft for an anticipated 7 mph landing.
> Control commands to the onboard, multispectral camera will be uploaded to
> the spacecraft. However, if NEAR goes faster or slower than anticipated,
> mission controllers at APL will be able to adjust the craft's onboard
clock
> to delay or advance the final photo sequence. "The spacecraft literally
> has to be in the right place at the right time" for the camera to function
> as planned, says Harch.
>
> Reflecting on the five-year mission, Harch says: "This final week has
been
> such an emotional one. It was an extraordinary experience working with
> these people to produce such a fabulous result, and all of us feel that
> way."
>
> Adds Bell, "Getting this altogether has meant many, many late nights."
>
>
>
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Received on Mon 05 Feb 2001 09:47:59 PM PST