Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Timing is critical as launch windows approach

06.09.2002

There will be greater tension than usual among engineers and scientists at Europe`s spaceport at Kourou, French Guiana, in January 2003, as they gather to see ESA`s comet-chasing spacecraft Rosetta departing on its long journey. If it is to keep its rendezvous with Comet Wirtanen in 2012, Rosetta must lift off on its Ariane-5 launcher no sooner than 03:40 CET on 13 January 2003 and no later than the end of that month.

This span of suitable dates is called a launch window. For interplanetary missions, such windows are much stricter than for satellites orbiting the Earth. To send a spacecraft from the ever-moving Earth to a planet or a comet following another course through space is highly complicated. Timing is everything. Before it can meet Comet Wirtanen, far out in space, Rosetta first has a series of planetary appointments to keep. With each close fly-by of a planet, it receives an energy boost because of the planet`s gravitational pull. The spacecraft is due to pass by Mars in August 2005, then do high-speed fly-bys of the Earth in November 2005 and November 2007.

In a way, Rosetta is like a passenger on a train journey involving several changes. Unless the first train leaves right on time, with the spacecraft on-board, it will miss the later connections. If it departed after 31 January 2003, Rosetta would be unable to reach the target comet.

"The cosmic clock of the Solar System fixed our launch date when Comet Wirtanen was selected as Rosetta`s target ten years ago," comments John Ellwood, project manager for the mission. "Although there are risks in a precise, rather short launch window, it`s had the advantage that everyone concerned knew there was no room for discussion - they had to be ready."

Besides the restricted span of launch dates, there is also a tight limit on the time of day at which Rosetta can leave Earth. Because the Earth rotates, Kourou must be correctly positioned in relation to the direction in which the spacecraft must head off, on the first leg of its interplanetary journey. The daily window is about 20 minutes, during which time the Earth rotates through 5 degrees.

In May 2003, similar concerns about a launch window will preoccupy the engineers and scientists of ESA`s Mars Express mission, at the Baikonur Cosmodrome in Kazakhstan, in the former Soviet Union. There the launcher will be a Soyuz-Fregat rocket. Scientists have always planned to use the especially favourable relative positions of Earth and Mars occurring in mid-2003 (and not repeated until 2020) for Mars Express to have an express flight to the Red Planet.

Opportunities to fly to Mars occur every 26 months, but the travelling distance varies a lot because the orbit of Mars is elliptical, that is, egg-shaped. The 2003 opportunity coincides with a time when the Earth is about to overtake Mars, as the planets orbit around the Sun, and when Mars happens to be in the closest sector of its orbit. The Mars Express launch window opens at 20:41 CET on 23 May 2003 and closes at 17:47 CET on 21 June 2003.

Almost nothing in space stands still with respect to Earth, so ESA`s scientists will have to be careful that their craft, Rosetta, leaves Earth at the right time and in the right way. The spacecraft has a long trip ahead.

Monica Talevi | AlphaGalileo
Further information:
http://www.esa.int

More articles from Physics and Astronomy:

nachricht Applicability of dynamic facilitation theory to binary hard disk systems
08.12.2016 | Nagoya Institute of Technology

nachricht Will Earth still exist 5 billion years from now?
08.12.2016 | KU Leuven

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>