STS-99

USA


Manned Flight nº: 215

Earth orbit Flight nº: 212

USA manned Flight nº: 128

97th Shuttle Mission - 14th Flight OV-105

Launch, orbit & landing data:

Designation 26088 / 00010A
Launch date - time 11 Feb 2000 - 17:43:40 UT
Launch site KSC, LC39A
Launch vehicle  Space Shuttle
Orbiter Endeavour F14 (OV-105)
Primary payload SRTM, EarthKAM
Mass (kg) 
Flight Crew Kregel, Gorie, Thiele
Kavandi, Voss, Mohri
Earth orbit on :
   - Perigee / Apogee 233 x 233 km
   - Inclination 57.0°
   - Period  min
Landing date - time 22 Feb 2000 - 23:22:23 UT
Landing location KSC, Runway 33
Flight Duration (d:hr:min) 11d 05h 39m
Nbr orbits 181

Crew

Nr. Surname Given name Job Flight
1  Kregel  Kevin Richard  CDR 11d 05h 39m 
2  Gorie  Dominic Lee Pudwill  PLT 11d 05h 39m 
3  Kavandi  Janet Lynn  MSP 11d 05h 39m 
4  Voss  Janice Elaine  MSP 11d 05h 39m 
5  Mohri  Mamoru  MSP 11d 05h 39m 
6  Thiele  Gerhard Julius Paul  MSP 11d 05h 39m 

Description:

Mission details:

Milestones:

OPF -- 12/15/98; VAB -- 7/11/99; PAD -- 12/13/99

Mission Objectives:

The Shuttle Radar Topography Mission (SRTM) is an international project spearheaded by the National Imagery and Mapping Agency and NASA, with participation of the German Aerospace Center DLR. Its objective is to obtain the most complete high-resolution digital topographic database of the Earth. SRTM consists of a specially modified radar system that will fly onboard the space shuttle during its 11-day mission. This radar system will gather data that will produce unrivaled 3-D images of the Earth's surface.

SRTM uses C-band and X-band interferometric synthetic aperture radars (IFSARs) to acquire topographic data of Earth's land mass (between 60 deg N and 56 deg S). It produces digital topographic map products which meet Interferometric Terrain Height Data (ITHD)-2 specifications (30 meter x 30 meter spatial sampling with 16 meter absolute vertical height accuracy, 10 meter relative vertical height accuracy and 20 meter absolute horizontal circular accuracy).

The result of the Shuttle Radar Topography Mission could be close to 1 trillion measurements of the Earth's topography. Besides contributing to the production of better maps, these measurements could lead to improved water drainage modeling, more realistic flight simulators, better locations for cell phone towers, and enhanced navigation safety. The data brought home by Endeavour's crew was collected during more than 222 hours of around-the-clock radar mapping operations and is enough to fill more than 20,000 CDs. The information gathered on the STS-99 Shuttle Radar Topography Mission will be used to produce global maps more accurate than any available today.

Orbit: Altitude: 233 km / Inclination: 57 deg

Data Statistics

In addition, this mission offers a number of applications for data products and science, including: geology, geophysics, earthquake research, volcano monitoring; hydrologic modeling; ecology; co-registration and terrain correction of remotely-acquired image data; atmospheric modeling; flood inundation modeling; urban planning; natural hazard consequence assessments; fire spread models; and transportation/infrastructure planning.

Civilian Applications

Enhanced ground collision avoidance systems for aircraft; civil engineering, land use planning, and disaster recovery efforts; and line-of-sight determination for communications, e.g., cellular telephones.

Military Applications

Flight simulators; logistical planning, air traffic management; missile and weapons guidance systems; and battlefield management, tactics.

Vehicle Data

Shuttle Liftoff Weight: 4,520,415 lbs. Orbiter/Payload Liftoff Weight: 256,560 lbs. Orbiter/Payload Landing Weight: 225,669 lbs.

Payload Weight: SRTM 14.5 tons

Software Version: OI-27

Space Shuttle Main Engines: SSME 1: 2052 SSME 2: 2044 SSME 3: 2047

External Tank: ET-92 ( Super Light Weight Tank)

SRB Set: BI-100/RSRM-71 SRTM Hardware--the Mast Payload Bay

The Mast

Made of carbon fiber reinforced plastic (CFRP), stainless steel, alpha titanium, and Invar, the mast is a truss structure that consists of 87 cube-shaped sections called bays. Unique latches on the diagonal members of the truss allow the mechanism to deploy bay-by-bay out of the mast canister to a length of 60 meters (200 feet), about the length of five school buses. The canister houses the mast during launch and landing and also deploys and retracts the mast.

The mast will be deployed and retracted by a motor-driven nut within the mast canister. This nut will pull the mast from its stowed configuration and allow it to unfold like an accordion. An astronaut inside the Space Shuttle will initiate the mast deployment, which will take about 20 minutes. The mast also may be deployed manually during an EVA using a hand-held motor if necessary.

The mast technology enables the SRTM system to perform at the high precision necessary to achieve the desired mapping resolution. The mast supports a 360-kilogram antenna structure at its tip and carries 200 kilograms of stranded copper, coaxial, fiber optic cables, and thruster gas lines along its length.

The Shuttle Radar Topography Mission Mast

The Main Antenna

The main antenna is connected to a pallet that in turn is bolted into the payload bay of the Space Shuttle. The system consists of two antennas and the avionics that compute the position of the antenna.

Each antenna is made up of special panels that can transmit and receive radar signals. One antenna is the C-band antenna and can transmit and receive radar wavelengths that are 2.25 inches or 5.6 centimeters long. The second antenna is the X-band antenna. This antenna can transmit and receive radar wavelengths that are 1.2 inches or 3 centimeters long. Both wavelengths were used in the Spaceborne Imaging Radar C-band/X-SAR missions in 1994 for a variety of environmental studies. The L-band antenna, also used during SIR-C/X-SAR, has been removed to save weight.

History/Background

Attitude and Orbit Determination Avionics

In order to map the Earth's topography, SRTM researchers will need to do two basic things:

1) Measure the distance from the Shuttle to some common reference, such as sea-level

2) Measure the distance from the Shuttle to the surface feature over which it is flying

For example, if the Shuttle's height above sea level is known and its respective height above a mountain, then researchers can subtract to get the height of the mountain above sea level.

For the first part, researchers need to know the Shuttle's height above sea level at all times. NASA will need to constantly measure the Shuttle position to an accuracy of 1 meter (about 3 feet).

For the second part of the formula, SRTM is using radar interferometry to measure the height of the Shuttle above the Earth's surface. One of the biggest challenges in making interferometry work is knowing the length and orientation of the mast at all times. Changes in its length and orientation can have a profound effect on the final height accuracy. Suppose the mast tip moves around by only 2 cm (a bit less than 1 inch) with respect to the Shuttle (this is something that is expected to happen during the mission, due to the astronauts moving around and Shuttle thrusters firing). That doesn't sound like much, but if not taken into account, it would result in a height error at the Earth's surface of 120 meters (almost 400 ft).

Researchers also expect changes in mast length of about 1 cm (about a half-inch) which if not detected would result in additional errors. Therefore, SRTM team members will need to constantly monitor the mast orientation and length. Part of this is measuring where the mast tip is relative to the Shuttle to better than 1 mm (about 4/100th of an inch). The other part is knowing how the Shuttle is oriented relative to the Earth to about 1 arcsec. An arcsecond is the angular size of a dime seen from a distance of 2 miles.

To keep track of the Shuttle's position, NASA will make use of the Global Positioning System (GPS). Mission managers do this by combining measurements taken by some specially designed GPS receivers being flown on the Shuttle with measurements taken by an international network of GPS ground receivers.

To measure the mast length and orientation, team members will use a variety of optical sensors. A target tracker will be used to follow a set of Light Emitting Diode (LED) targets which can be seen on the outboard radar antenna once the mast is fully deployed.

The target tracker also is used to monitor the antenna alignment. There are laptop computers on the Shuttle which display the antenna alignment (kind of a cross-hairs with a dot, representing the alignment error). The crew will use these displays to guide adjustment of some motors at the mast tip (the "milkstool") to remove any alignment errors so the radar can operate properly.

To get the most accurate measure of the mast length, SRTM managers will use a set of rangefinders, called Electronic Distance Measurement (EDM) units. To save time and money, the SRTM team decided to buy commercial surveying instruments and modify them for use in space. The rangefinders work by bouncing a beam of light off a special corner-cube reflector on the outboard antenna and measuring the time to determine the distance.

To measure the orientation of the Shuttle with respect to the Earth, mission managers will use one of the most precise star tracker and gyroscope packages ever built. The star tracker looks at the sky and compares what it sees with a star catalogue in its memory to get the attitude of the Shuttle.

EarthKAM In-Cabin

Prime: Kevin Kregel Backup: Dom Gorie

EarthKAM is a NASA-sponsored program that enables middle school students to take photographs of the Earth from a camera aboard the Space Shuttle. During missions, students work collectively and use interactive web pages to target images and investigate the Earth from the unique perspective of space.

An electronic still camera (ESC) bracket-mounted to the overhead starboard window of the orbiter aft flight deck will face the nadir to observe various student-selected sites on Earth. Other than equipment setup, initial camera pointing, and possible camera lens changes, no crew intervention is required for nominal operations.

The University of California at San Diego houses the EarthKAM Mission Operations Center (MOC). Most participating schools (or group of schools) establish a Student Mission Operation Center (SMOC) whose computers are connected to the Internet.

Before the mission, students select a topic of interest, such as human settlement patterns, mountain ranges, or agricultural patterns. Then they define investigations that will be supported by the EarthKAM images.

During the mission, each SMOC submits a number of photo requests through specialized EarthKAM web pages. The requests are processed and uplinked to the EarthKAM ESC aboard the Shuttle.

After the ESC takes the pictures, digital images are sent back to Earth and posted on the data system for the students to use in their investigations. For their final reports, students use these new images along with other relevant images from the full EarthKAM image set. Scientists and educators review the original proposal and the final report to provide feedback to the students.

The EarthKAM program also is preparing to mount a camera aboard the International Space Station.

History/Background

During the first four missions of EarthKAM, students took more than 2,000 high-resolution digital images of the Earth. These photographs included the Himalayas, clouds over the Pacific, volcanoes, and recent forest fires in Indonesia.
REF #6 (RVdownload) model


Astrophilately covers:

STS 99

Launch cancel KSC. Credit: J. Vd Dr.

STS 99

Machine launch cancel KSC, signed by 3 astronauts. Credit: #402


STS 99

Start Tracking mission Houston, signed by Thiele. Credit: #402

STS 99

Landing cancel KSC. Credit: J. Vd Dr.



Ref.: #7(JR419,421), #8, #16, #402, #415 - update: 05.04.19 Home