Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.stecf.org/conferences/adass/adassVII/reprints/hiltonp.ps.gz Äàòà èçìåíåíèÿ: Mon Jun 12 18:51:46 2006 Äàòà èíäåêñèðîâàíèÿ: Tue Oct 2 03:27:56 2012 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: solar system

Astronomical Data Analysis Software and Systems VII
ASP Conference Series, Vol. 145, 1998
R. Albrecht, R. N. Hook and H. A. Bushouse, e
Ö Copyright 1998 Astronomical Society of the Pacific. All rights reserved.
ds.
ASCA: An International Mission
P. Hilton
Hughes International/ISAS, 3­1­1 Yoshinodai, Sagamihara, Kanagawa
229, Japan
A. Antunes
Hughes STX/GSFC Greenbelt, MD 20771
Abstract. The ASCA X­ray satellite mission involves scientists from
Japan, America, and Europe. Each year more than 400 targets are ob­
served by ASCA. The process starts with the electronic submission of
a proposal and ends with the delivery of a data tape. A successful ob­
servation depends on organization within the operations team and ef­
ficient communication between the operations team and the observers.
The methods used for proposing, scheduling, coordinating observations,
quick­look plots, and data delivery are presented. Cooperation is the key
to success in an international mission
1. Introduction
ASCA is an X­ray satellite which was launched by Japan in 1993. While the
platform is Japanese, the hardware was a joint e#ort by US and Japanese teams.
The entire processing cycle from proposal submission through data delivery is
a joint e#ort between the two countries. In short, the ASCA project must
coordinate across continents and languages. To help with the coordination,
NASA has agreed to support one person on site at ISAS.
Observation time is allocated 50% Japan only, 25% US­Japan, 15% US
only, and 10% ESA­Japan. The ESA time is granted by Japan to encourage
international collaboration. A typical observation is for 40 kiloseconds, or about
one day of satellite time. Some pointings are as short as 10 ksec; some are as
long as 200 ksec. Over the course of a year over 400 observations are made by
ASCA, many of these are coordinated with other astronomical platforms.
In order to produce science, these 400 observations must be proposed, co­
ordinated and scheduled, and observed. Then, quicklook and production data
must be delivered to the scientists.
2. Announcement and Proposals
The entire process begins with a coordinated announcement by ISAS, NASA,
and ESA, 90 days before the deadline. Requests for proposals are made in the
vernacular of each country. A proposal has two parts: a cover page and scientific
267

268 Hilton and Antunes
justification. The cover page includes contact information about the proposer
and co­investigators, the abstract, target data, and observational requirements.
English is used for the cover page while either English or Japanese is acceptable
for the scientific justification in Japan.
ASCA is one of the first missions that required electronic submission of the
cover page. Electronic submission of proposals allows the database to be pop­
ulated automatically. The database then serves as the common reference point
for each country's e#orts, and thus the e­mail proposals are used throughout the
observation cycle.
In order to get 100% compliance with electronic submission, we had to
provide multiple avenues and make it easy for users. Proposers can construct
their cover page via a form on the World Wide Web or a blank e­mail form.
About 70% of the Japanese proposals submitted in 1996 used the blank form,
while 70% of the US proposers used Web forms. The Web version has many
pull­down menus and on­line help. The e­mail method continues to be supported
because it still has an active user base.
The Remote Proposal System (RPS) developed at Goddard for preparing,
checking, and sending proposals is used. RPS, which is used by other missions
including XTE and ROSAT, is available over the Web. RPS is used to check
each proposal for format accuracy before it is accepted.
3. Re­order/Review, and Approval
After the proposal deadline, invalid proposals such as duplicates or withdrawn
ones are eliminated. Proposals are re­ordered according to category and postal
code. A five digit number is assigned to each proposal. This number starts with
the AO, and the PI's country code. The proposal number is the key reference
through the observation and data distribution.
Formal panels in Japan, America, and Europe review the proposals. A
merging meeting convenes to decide the final target list. Email is then used to
notify the PIs that their target has been selected. The list of accepted targets
is also made public via the Web. This provides both an active and a passive
electronic disbursement of the final selection, and reduces miscommunication and
communications breakdowns. Selected targets are assigned a sequence number
which serves as the main identifier of the observation.
4. Long­term Scheduling
ASCA uses a schedule planning program called SPIKE which was developed at
MIT for the Hubble project. The details of SPIKE are beyond the scope of this
paper. In general, we plan the time criticals according to the proposal requests
and we use a sun angle constraint of +/­ 25 degrees.
SPIKE produces a one­year schedule which is divided into weekly periods.
One output file is a nice readable ASCII file, which is run through a Perl script
to make an HTML file for use on the Web. The long­term schedule displays the
list of targets and the planned or observed date. Each target has a hyperlink to
its proposal summary.

ASCA: An International Mission 269
The proposal summary displays the abstract and the successful targets from
the proposal. Comments are listed when they are included with the proposal.
There are e­mail hyperlinks to the PI and primary Co­I. This summary serves
both the community and the operations team.
5. Co­ordination
Sometimes a PI will request observation time on more than one platform, or with
a ground station. Since the observation cycles of each platform are di#erent
and in general independent, it is the responsibility of the PI to note that a
co­ordinated observation is required.
Then, it becomes necessary to communicate with other schedulers. Usually,
an e­mail conveys the list of common targets and a general schedule is discussed.
Email has low overhead and fast response time. The primary disadvantage, of
course, is that it is ultimately people­based. No mechanism exists (or has ever
been proposed) to unify satellite scheduling. Once a coordinated observation
is approved, it is solely the responsibility of the schedulers (in consultation, as
needed, with project PIs) to make sure the coordination happens.
There is a network of schedulers that was organized by Dave Meriwether
when he was at EUVE. Unfortunately, we have not kept the system going after
Dave's departure from EUVE. We need to get this network back on track.
6. Short­term Schedule
Short­term schedules of 10­13 days are made about one month in advance. ASCA
uses a short­term schedule editor called Needle that was developed in­house at
GSFC/ISAS. The primary considerations for a short term schedule are time­
critical requests, uno#cial time critical requests, bright earth, and star tracker.
After the short term schedule is made, some post processing of the file to be
distributed takes place. The latest e­mail address and institute name of the PI
are added for the convenience of the contact scientist. Also, relevant comments
from the proposal are added. This file is sent to the operations teams in both
Japan and the US via e­mail.
After the schedule has been finalized, PIs are notified in English about their
upcoming observation. This gives the PI a chance to prepare for the observation
in advance of hearing from the contact scientist. By the time the contact scientist
notifies the PI, we will have completed several other short term schedules. This
means that late notification of a PI could a#ect the scheduling process. Early
notification seems to work in the best interest of both the operations team and
the PI.
After the targets have been scheduled and the PIs have been notified,
changes are sometimes required. It is important to notify a PI when an ob­
servation schedule is changed. ASCA TOOs are subjected to review before
approval by two team members in Japan and two in the US. Rapid communica­
tions via e­mail or fax means that a gamma ray burst can be reported, discussed,
scheduled, and observed by ASCA within 36 hours.

270 Hilton and Antunes
7. Observation and Quick­look Plots
A week or two prior to an observation, the PI is contacted for detailed arrange­
ments. The Japanese contact Japanese PIs, while the US team contacts US and
ESA PIs. Email is the primary method of contact.
The ASCA operations ground control center is located at Kagoshima Space
Center (KSC) on the south island of Japan. KSC is operated six days a week.
When the station is manned, it is possible to do a quick­look plot of data. These
plots are distributed via fax.
Electronic delivery would be a useful method to pass the quicklooks along
to the PIs. However, the current system is not set up for this, and so a fax
machine is used.
8. Data Delivery
After the observation has been made, first reduction files (frf) are sent to ISAS
and to Goddard. Japanese PIs are able to process their own data before the
CDs are sent out. Finally, the observation data tapes are made and the data
are sent to Goddard for storage and distribution. Data are placed on a CD­
ROM and mailed to the PI. Because the data have been tagged with the same
ID as the schedule products, cross­correlating is trivial. And, the community
is automatically aware (by reading the schedule) what products are available in
the archive. Data are made public after 1­2 years. This means that the Web­
based notification we provide also serves as a ``promotional teaser'' for upcoming
data. The electronic transfer process ensures that data are not lost, misplaced,
or wrongly labeled.
The process does require manipulation of the data at di#erent stages, and
some manual intervention. A more automated pipeline would be an asset. The
most important aspect is that the entire process is transparent to the user. The
user sends in an e­mail or Web proposal, and later receives their data (as a CD
in the mail, or electronically from the archive.)
9. Summary
ASCA is a very successful mission. Part of the success of the ASCA mission is
due to the rapid communication channels that are available to us. We require
that all proposers use a standard e­mail format in English. We use the language
of each country, when appropriate. English is used as the common language.
When we need to coordinate with other schedulers, we receive timely sup­
port. We use the Internet, e­mail, and faxes for communications within the
ASCA community. The ultimate strength of the electronic process is that it
facilitates better communication, and eliminates the geographic boundaries of
this project.
The true reason for ASCA's success is the cooperation of the guest observer
teams in Japan, the US, and Europe. We can have the best communications
system, but without the cooperation of the operation teams, we would have
little.