The first EQUARS workshop took place between the 28th and 30th of November, 2001. The purpose of this workshop was to bring together the various science teams and engineering groups that will be responsible for the satellite. The workshop was held at the Satellite Integration and Test Laboratory, LIT, INPE, Sao Jose dos Campos, SP, Brazil. It was a productive meeting, achieving its purpose of clarifying the mission objectives and initiating and re-enforcing the necessary information flow between the project coordination, the various science teams involved, and INPE's satellite engineering group.

The following paragraphs present a brief summary of the history of the project to date, including a description of the initial mission objectives and projected satellite parameters. Final details of the project are still fluid, and will not be defined until a later date, when the various teams involved have had time to consolidate their ideas in the light of the discussions that took place at the Workshop.

Mission: The scientific mission of EQUARS was defined by the satellite project committee of INPE's Aeronomy division, i. e., Global scale monitoring of the Earth’s equatorial low, middle and upper atmosphere-ionosphere. The main objective is to study dynamical, photochemical and ionospheric processes in the equatorial low, middle and upper atmosphere, with special emphasis on vertical energy transport, propagation of gravity, tidal and planetary scale waves, and the generation and development of plasma bubbles in the ionosphere.

Justification of the project: From our recent knowledge of dynamical processes in the Earth’s middle and upper atmosphere, it is well known that the equatorial atmosphere plays an important role with respect to energy sources, transport, and global circulation. With the generation of atmospheric gravity waves in the troposphere and tidal forcing in the stratosphere, the equatorial atmosphere plays a significant role in the propagation of these wave energies to the upper atmosphere and ionosphere. Furthermore, deposition of momentum and energy in the upper atmosphere generates large scale travelling waves (planetary waves) and ionospheric disturbances (plasma bubbles). These waves in turn propagate to middle and high latitudes. It is only in recent years that an integrated picture of the energy balance of the upper atmosphere is beginning to emerge. There can be no doubt that we need better global data if we are to understand the forces at work.

The Brazilian National Institute for Space Research, INPE, has been working in the area of space science and technology since 1962. The investigation of the equatorial atmosphere, including global scale climate change and ionospheric phenomena, is a major activity at INPE. For this reason a satellite-based observation system for monitoring the equatorial atmosphere on a global scale was proposed by the Brazilian scientific community. Recent global scale measurements of the upper atmosphere organized by PSMOS/SCOSTEP have also shown the necessity for global scale observation. In the SCOSTEP program, EPIC, attention is being focussed on coupling mechanisms in the equatorial middle and upper atmosphere. We hope that the EQUARS satellite will make an important contribution to these programs.

Satellite Characteristics: The following parameters have been defined as a starting point for both scientific and engineering purposes:

• Orbit: Equatorial, with inclination ≤ 25 degrees,
• Altitude: 700 – 800 km (LEO),

• Total payload mass: 30 kg,
• Available volume for Payload: 60 x 70 x 30 cm,
• Orientation of satellite axis: towards the Earth's surface,
• Spin axis: no spin
• Attitude Control: active 3 axis control with precision better than 1 degree.
• Power Available to the Payload : » 30 W
• Memory available to the payload: » 800 Mbits/24 hours

Proposed scientific instruments: In May 2001, at the end of the period stipulated in the announcement of opportunity, six proposals were accepted as possible candidates for the mission. The 6 instruments are summarized in Table 1. According to the experiments proposed, the following phenomena will be investigated: tropospheric convection, lightning, gravity wave propagation from troposphere to mesosphere, influence of dynamical processes in the temperature field, generation of ionospheric irregularities.

Table 1. Experiments proposed for EQUARS

	1	2	4	3	5	6
Experiment	GPS Occultation	ONDINA	GWIM	MELITS	Airglow monitor	Plasma sensors
Instrument	GPS Receiver	Sprite Imager	CCD imager	IR Imager	4 channel photometer	Plasma sensors
Principal Investigator	T. Tsuda	D. Sentman	R. Lowe	M. Taylor	H. Takahashi	M. Abdu
Institution	RASC/Kyoto-University, Japan	UAF/USA	UWO/Canada	USU/USA	INPE	INPE
Measurement	Water vapor, Temperature, Total Electron Content	Sprites and Lightning	Gravity waves	OH temperature	OH OI5577 OI6300	Electron density, Tec

Experiment descriptions

Details of the experiments proposed are available in the following files, which contain most of the material presented at the workshop:

GWIM

EQUARS_nov27.pdf

GWIM_EQUARS_8.pdf

gwim_power.pdf

GPS

cosmic_equars_brazil_talk1_pub.pdf

EQUARS.pdf

EQUARS2001.pdf

gps_data_assim_brasil.pdf

GPS_sci_oview.pdf

Airglow

Airglow monitor.pdf

MELITS

EQUARS-v-graphs.pdf

MTaylor.pdf

ONDINA

Equars Ondina.pdf

Plasma Probes

Plasma PDP_WorkshopR1.pdf

Satellite description

Information on the proposed satellite configuration is provided in the following files:

Satellite Engineering

AMechanical.pdf

Electrical Architecture.pdf

EquarsSys.pdf

Introduction.pdf

Mission Analysis.pdf

WorkshopEQUARS.pdf

Acknowledgment: The organizers of the workshop take this opportunity to thank all of the participants, especially those making presentations, whose presence made the success of the meeting possible. Especially gratifying was the presence of three participants from Mexico and Chile, with whom it was possible to discuss future satellite programs in Latin America. A list of participants follows.

Workshop participants

Toshitaka Tsuda	RASC, Kyoto University	tsuda@kurasc.kyoto-u.ac.jp
Christian Rocken	UCAR, Boulder, USA	rocken@ucar.edu
Davis Daniel Sentman	UAF, Alaska, USA	dsentman@gi.alaska.edu
Fernanda de São Sabbas Tavares	UAF, Alaska, USA	fssabbas@gi.alaska.edu
Robert Peter Lowe	UWO, London, Canada	lowe@danlon.physics.uwo.ca
Kathleen Linda Gilbert ,	UWO, London, Canada	kgilbert@physics.uwo.ca
Neil Rowlands	UWO, London, Canada	rowlands.n@ems-t.com
Michael John Taylor ,	USU, Logan, USA	mtaylor@cc.usu.edu
John kemp	USU, Logan, USA
Marina Stepanova	U. Santigo, Chile	mstepano@lauca.usach.cl
Raul Labbe	U. Santigo, Chile	rlabbe@lauca.usach.cl
Jose Francisco Valdes Galicia	U. N. Mexico,	jfvaldes@tonatiuh.igeofcu.unam.mx
João Francisco Galera Minico UNESP/P. Prudente	UNESP, P. Prudente, SP	galera@prudente.unesp.br
Luiz Fernando Sapucci/UNESP	UNESP, P. Prudente, SP	sapucci@prudente.unesp.br
José Tadeu G. Tommorelli	UNESP, P. Prudente, SP	tadeu@prudente.unesp.br
Pierre Kaufman	U. Mackenzie, SP	kaufmann@tayi.craae.mackenzie.br
Rui Tertuliano de Medeiros	UFRN, Natal	rui@dfte.ufrn.br
Ricardo Arlen Buriti da Costa	UFPB, Campina Grande	rburiti@df.ufpb.br
Odylio Denys de Aguiar	INPE	odylio@das.inpe.br
Carlos E Santana	INPE	santana@dss.inpe.br
Himilcon C Carvalho	INPE	carvalho@dss.inpe.br
Mário Marcos Quintino da Silva	INPE	quintino@dss.inpe.br
Sebastião Varotto Corsatto	INPE	varotto@dem.inpe.br
Arcélio C. Louro	INPE	aclouro@dss.inpe.br
Roberto Vieira da Fonseca Lopes	INPE	rvfl@dem.inpe.br
Walter D Gonzalez	INPE	gonzalez@dge.inpe.br
M A Abdu	INPE	abdu@dae.inpe.br
Polinaya Muralikrishna	INPE	murali@dae.inpe.br
Barclay Clemesha	INPE	clem@laser.inpe.br
Inez S Batista	INPE	inez@dae.inpe.br
Hisao Takahashi	INPE	hisao@laser.inpe.br

 

Photo provided by Marina Stepanova