STEX

{{Infobox spaceflight

| name = Science Technology Experiments

| names_list = STEX
USA 140
NROL-8

| image = 300px

| image_caption = STEX during ground-testing

| image_alt =

| image_size =

| mission_type = Technology demonstration

| operator = NRO

| Harvard_designation =

| COSPAR_ID = 1998-055A

| SATCAT = 25489

| website =

| mission_duration =

| distance_travelled =

| orbits_completed =

| suborbital_range =

| suborbital_apogee =

| spacecraft =

| spacecraft_type =

| spacecraft_bus =

| manufacturer = Lockheed Martin

| launch_mass = {{Convert|539.4|kg|abbr=on}}

| BOL_mass =

| landing_mass =

| dry_mass =

| payload_mass =

| dimensions =

| power =

| launch_date = {{start date|1998|10|03|10|04|49|7=Z}}

| launch_rocket = Taurus (rocket)

| launch_site = Vandenberg AFB

| launch_contractor =

| deployment_from =

| deployment_date =

| entered_service =

| disposal_type =

| deactivated =

| destroyed =

| last_contact =

| recovery_by =

| recovery_date =

| decay_date =

| landing_date =

| landing_site =

| orbit_reference =

| orbit_regime =

| orbit_longitude =

| orbit_slot =

| orbit_semimajor =

| orbit_eccentricity =

| orbit_periapsis =

| orbit_apoapsis =

| orbit_inclination =

| orbit_period =

| orbit_RAAN =

| orbit_arg_periapsis =

| orbit_mean_anomaly =

| orbit_mean_motion =

| orbit_repeat =

| orbit_velocity =

| orbit_epoch =

| orbit_rev_number =

| apsis =

| trans_band =

| trans_frequency =

| trans_bandwidth =

| trans_capacity =

| trans_coverage =

| trans_TWTA =

| trans_EIRP =

| trans_HPBW =

| insignia =

| insignia_caption =

| insignia_alt =

| insignia_size =

}}

Space Technology Experiments, or STEX, also known as NRO Launch 8 or NROL-8, was an experimental National Reconnaissance Office (NRO) satellite built by Lockheed Martin. It was launched on 3 October 1998.{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1998-055A |title=STEX |publisher=NSSDC Master Catalog Search |date=8 October 2010}} One of the experiments was ATEx (Advanced Tether Experiment), which was deployed on 22 January 1999, and subsequently jettisoned.{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1998-055C |title=ATEx |publisher=NSSDC Master Catalog Search |date=8 October 2010}}

ATEx

File:Atex.jpg

The Advanced Tether Experiment (ATEx), was a follow on to the TiPS experiment, designed and built by the Naval Center for Space Technology, flown as one of the experiments on STEX. ATEx had two end masses connected by a polyethylene tether that was intended to deploy to a length of 6 km, and was intended to test a new space tether deployment scheme, new tether material, active control, and survivability. ATEx was deployed on 16 January 1999 and ended 18 minutes later after deploying only 22 m of tether. The jettison was triggered by an automatic protection system designed to save STEX if the tether began to stray from its expected departure angle,{{cite web |agency=U. S. Naval Research Laboratory |url=https://www.nrl.navy.mil/ssdd/programs/atex/ |title=Advanced Tether Experiment (ATEx) |url-status=live |archive-url=https://web.archive.org/web/20150906141352/http://www.nrl.navy.mil/ssdd/programs/atex |archive-date=6 September 2015 }} which was ultimately caused by excessive slack tether.{{cite journal |url=https://arc.aiaa.org/doi/abs/10.2514/2.3655 |doi=10.2514/2.3655 |title=Advanced Tether Experiment Deployment Failure |journal=Journal of Spacecraft and Rockets |volume=38 |issue=1 |date=January–February 2001 |pages=60{{hyphen}}68 |last1=Gates |first1=Stephen S. |last2=Koss |first2=Stephen M. |last3=Zedd |first3=Michael F. |bibcode=2001JSpRo..38...60G }} As a result of the deployment failure, none of the desired ATEx goals were achieved.{{cite web |last=Kramer |first=Herbert J. |url=https://directory.eoportal.org/web/eoportal/satellite-missions/s/stex |title=STEX (Space Technology Experiment) / ATEx |website=eoPortal |publisher=European Space Agency |access-date=18 January 2022}} ATEx is now tracked as a separate object as USA 141 or COSPAR ID 1998-055C.{{cite web |title=NSSDCA – STEX – Details |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1998-055A|website=nssdc.gsfc.nasa.gov |agency=NASA |accessdate=23 June 2016}}

References

External links

[http://space.skyrocket.de/doc_sdat/stex.htm STEX] at Gunter's Space Page

Category:Spacecraft launched in 1998

Category:Satellites of the United States