astronomy

High Energy Transient Explorer 1

High Energy Transient Explorer 1 is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand High Energy Transient Explorer 1 rather than just read about it. In short: High Energy Transient Explorer 1 (HETE-1) was a NASA astronomical satellite with international participation (mainly Japan and France). History The concept of a satellite capable of multi-wavelength observations of gamma-ray bursts (GRB) was discussed at the Santa Cruz, California meeting on GRBs in 1981.

Key takeaways

High Energy Transient Explorer 1 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect High Energy Transient Explorer 1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of High Energy Transient Explorer 1 from memory before moving on to harder problems.

Reference excerpt

High Energy Transient Explorer 1 (HETE-1) was a NASA astronomical satellite with international participation (mainly Japan and France).

History The concept of a satellite capable of multi-wavelength observations of gamma-ray bursts (GRB) was discussed at the Santa Cruz, California meeting on GRBs in 1981. In 1986, the first realistic implementation of the HETE concept by a Massachusetts Institute of Technology MIT-led International Team was proposed. This concept, which was adopted, emphasized accurate locations and multi-wavelength coverage as the primary scientific goals for a sharply-focused small satellite mission which would ultimately solve the gamma-ray burst mystery. In 1989, NASA approved funding for a low-cost "University Class" explorer satellite to search for GRBs. In 1992, the HETE-1 program was funded, and the design and construction of HETE-1 began. The original spacecraft contractor for HETE-1 was AeroAstro, Inc., of Herndon, Virginia. AeroAstro was responsible for the spacecraft bus, including power, communications, attitude control, and computers. The instrument complement for HETE-1 consisted of four wide-field gamma-ray detectors, supplied by the CESR of Toulouse, France. A wide-field coded-aperture X-ray imager, supplied by a collaboration of Los Alamos National Laboratory (LANL) and the Institute of Chemistry and Physics (RIKEN) of Tokyo, Japan. Four wide-field near-UV CCD cameras, supplied by the Center for Space Research at the Massachusetts Institute of Technology. Due to the tragic fate of HETE-1 and the continuing timeliness of GRB science, NASA agreed to a reflight of the HETE-1 satellite, using flight spare hardware from the first satellite. In July 1997, funding for a second HETE satellite was granted, with a target launch date early 2000.

Mission The prime objective of HETE-1 was to carry out the first multi-wavelength study of GRBs with ultraviolet (UV), X-ray, and gamma-ray instruments mounted on a single, compact spacecraft. A unique feature of the HETE-1 mission was its capability to localize GRBs with ~10 arcseconds accuracy in near real time aboard the spacecraft, and to transmit these positions directly to a network of receivers at existing ground-based observatories enabling rapid, sensitive follow-up studies in the radio, infrared (IR), and visible light bands.

Spacecraft The satellite bus for the HETE-1 satellite was designed and built by AeroAstro, Inc. (USA) of Herndon, Virginia. The HETE-1 spacecraft was Sun-pointing with four solar panels connected to the bottom of the spacecraft bus. Spacecraft attitude was to be controlled by magnetic torque coils and a momentum wheel.

Experiments

Omnidirectional Gamma-Ray Spectrometer The Omnidirectional Gamma-Ray Spectrometer was designed to operate from 6 keV to greater than 1 MeV. The instrument consisted of four wide-field gamma-ray detectors with a total effective area of 120 cm2 (19 sq in). The HETE satellite remained within the launch vehicle due to battery failure. The experiment was unable to operate.

Ultraviolet Transient Camera Array The Ultraviolet Transient Camera Array was designed to provide accurate directional information on transient events, and to assist with spacecraft attitude determination. The instrument consisted of four ultraviolet Charge-coupled device (CCD) cameras operating in the 5 to 7 eV range.

Wide Field X-ray Monitor The Widefield X-ray Monitor was designed to perform X-ray studies of gamma-ray bursts. The instrument consisted of coded aperture cameras, sensitive in the 2-25 keV energy range, and with location accuracy to ~ 10 arcminutes or better.

Launch

The HETE-1 satellite was launched with the Argentina satellite SAC-B. HETE-1 was lost during the launch on 4 November 1996, at 17:08:56 UTC, from Wallops Flight Facility (WFF), launch area-3. The Pegasus XL launch vehicle achieved a good orbit, but explosive bolts releasing HETE-1 from another satellite, SAC-B, and from its Dual Payload Attach Fitting (DPAF) envelope failed to charge, dooming both satellites. A battery on the third stage of the launch vehicle and responsible for these bolts cracked during the ascent. Due to its inability to deploy the solar panels, HETE lost power several days after launch.

Atmospheric entry HETE-1 re-entered on 7 April 2002.

Worked examples

Example 1 — a first encounter with High Energy Transient Explorer 1

Start with the simplest possible case. Write down what High Energy Transient Explorer 1 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to High Energy Transient Explorer 1 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about High Energy Transient Explorer 1 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of High Energy Transient Explorer 1

In research: High Energy Transient Explorer 1 appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses High Energy Transient Explorer 1 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: High Energy Transient Explorer 1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Explorers Program, Gamma-ray telescopes, Satellites orbiting Earth, so understanding it makes those chapters shorter.
In everyday life: Look for High Energy Transient Explorer 1 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study High Energy Transient Explorer 1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what High Energy Transient Explorer 1 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain High Energy Transient Explorer 1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is High Energy Transient Explorer 1 in simple terms?

High Energy Transient Explorer 1 (HETE-1) was a NASA astronomical satellite with international participation (mainly Japan and France). History The concept of a satellite capable of multi-wavelength observations of gamma-ray bursts (GRB) was discussed at the Santa Cruz, California meeting on GRBs i…

Why does High Energy Transient Explorer 1 matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study High Energy Transient Explorer 1?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on High Energy Transient Explorer 1.