JAXA - Akatsuki - Venus Climate Orbiter (PLANET-C)

[johnxx9]

Program thread for Akatsuki.

The launch campaign thread is in the Japanese sub-forum.

LIVE: H-IIA - Akatsuki - Venus Climate Orbiter (PLANET-C) - May 20, 2010


The PLANET-C is supposed to be launched at the beginning on 2010 and will be the first mission to Venus in almost 20 years. Unlike Mars, not many missions are scheduled for Venus. Nine until the next 10 years (Venera-D and Venus Entry Probe).

http://www.jaxa.jp/projects/sat/planet_c/index_e.html

[ugordan]

The PLANET-C is supposed to be launched at the beginning on 2010 and will be the first mission to Venus in almost 20 years. 

Um, I know it may look like the mission doesn't even exist judging by the lack of press releases, but aren't you forgetting ESA's Venus Express?

[johnxx9]

The PLANET-C is supposed to be launched at the beginning on 2010 and will be the first mission to Venus in almost 20 years. 

Um, I know it may look like the mission doesn't even exist judging by the lack of press releases, but aren't you forgetting ESA's Venus Express?

Sorry! My bad! I had the Magellan probe in mind.

[kevin-rf]

Didn't Messenger do a flyby on the way to Mercury taking science data in 2007?

[eeergo]

Didn't Messenger do a flyby on the way to Mercury taking science data in 2007?

Yes, it even collaborated with Venus Express in a set of observations.

http://www.esa.int/esaMI/Venus_Express/SEMMC0ARR1F_0.html

[akari]

Solar powered sail demonstrator IKAROS and the university satellite UNITEC-1 which are launched at the same time will reach to Venus in December, 2010, too.
If IKAROS is lucky, it will survive.
But maybe, I think that UNITEC-1 does not survive till the arrival to Venus.

http://www.jspec.jaxa.jp/e/activity/ikaros.html
http://unitec-1.cc.u-tokai.ac.jp/en/news_en

[Hungry4info3]

The Cassini spacecraft also visited Venus.

[jacqmans]

----------------------------------------------------------------------
                       ***  JAXA MAIL SERVICE  ***
                   Japan Aerospace Exploration Agency
----------------------------------------------------------------------
          Venus Climate Orbiter "PLANET-C" Nicknamed "AKATSUKI"

                                                October 23, 2009 (JST)
                                    Japan Aerospace Exploration Agency

The Japan Aerospace Exploration Agency (JAXA) is scheduled to launch
the Venus Climate Orbiter "PLANET-C" in Japan Fiscal Year 2010.
JAXA has decided the nickname of the PLANET-C as follows.

1. Name: Venus Climate Orbiter "AKATSUKI" (meaning "Dawn")

2. Reasons for naming:
- The name was discussed and decided by the PLANET-C project team.
- "AKATSUKI" means "dawn" when Venus shines most brightly as the first
  graying of dawn appears in the east sky just prior to sunrise. The
  AKATSUKI is scheduled to arrive at Venus, which beautifully shines
  as the "morning bright star" at dawn, in the winter of 2010. The
  name also reflects the purpose of the PLANET-C project to newly
  create planetary meteorology by exploring Venus. The word "AKATSUKI",
  which indicates the start of a day, implies not only a beautiful
  scenic image, but also the power of achieving a goal, thus the name
  carries the thoughts and determination toward the success of the
  mission.
- By publishing the nickname well in advance of its launch, we intend
  to make people more familiar with the satellite and its launch
  preparations, actual launch, and on-orbit operations.

Reference
http://www.jaxa.jp/press/2009/10/20091023_akatsuki_e.html#at

This page URL:
http://www.jaxa.jp/press/2009/10/20091023_akatsuki_e.html
---------------------------------------------------------------------

[jacqmans]

----------------------------------------------------------------------
                       ***  JAXA MAIL SERVICE  ***
                   Japan Aerospace Exploration Agency
----------------------------------------------------------------------
    Venus Climate Orbiter "AKATSUKI" (PLANET-C) Message Campaign   

                                                October 23, 2009 (JST)
                                    Japan Aerospace Exploration Agency

The Japan Aerospace Exploration Agency (JAXA) is scheduled to launch
the Venus Climate Orbiter "AKATSUKI" (PLANET-C) by H-IIA Launch
Vehicle in Japan Fiscal Year 2010. The AKATSUKI will enter the orbit
of Venus about half a year after its launch, and will take some two
years to explore the atmosphere of Venus.
JAXA would like to enhance people's interest in space and the Earth
by holding a "message campaign" in which we invite people to send us
messages that will be printed in fine letters on an aluminum plate
and placed aboard the Venus Climate Orbiter "AKATSUKI". We will accept
messages both from Japan and overseas so that we can bind the
feelings and thoughts of everybody in the world into one, and inject
it into the orbit of Venus. Through this campaign, we would like to
boost the public's knowledge about Japanese space science research
activities in Japan as well as abroad.
With the cooperation of the "International Year of Astronomy 2009
Japan Committee," we would like to carry out the "message campaign"
to collect messages to be attached to the Venus Climate Orbiter
"AKATSUKI" as follows.

1. Campaign name
   "We will deliver your message to the bright star Venus"
   - "AKATSUKI" Message Campaign -

2. Message accepted
   From October 23, 2009 thru December 25, 2009 (Japan Standard Time)

3. How to send your message
   [For individual senders]
   Through the Internet
   Japanese site: http://www.jaxa.jp/event/akatsuki/index_j.html
   English site: http://www.jaxa.jp/event/akatsuki/index_e.html

 - You can send a message in Japanese characters (Hiragana, Kanji,
   and Katakana) as well as using numbers and/or Roman letters.
   However, some letters (such as half-sized Katakana) or some PC
   specific letters may not be properly encoded on our side. Therefore,
   if you use such letters, they may not be printed as you intend.
 - Only a name (without a message) is also acceptable.
 - The International Year of Astronomy 2009 Japan Committee will be in
   charge of accepting names and messages sent through the Internet,
   counting them, and protecting your private information.
 - Your message and illustration may be used on our Web site, leaflet,
   and/or magazines for the purpose of public affairs and promotion.
   Copyright of the messages and illustrations basically belong to JAXA.

   [Sending a message as a group]
   Those who are a group of over 100 members in Japan (such as a
   school, kindergarten, company, residents' association, hobby's
   club, science museum, or event organization team) can send a
   message via conventional postal mail. Please write your message as
   large and clearly as possible within a limited paper size (A4). We
   can accept an illustration, but please remember that everything
   will be carved in black and white. Send your group name and a
   message on an A4 size paper (if your paper size is different,
   please make a contraction /enlargement copy to make it size A4)
   and write the following on the backside of the paper: the number
   of people in your group (over 100 people is the norm), the address,
   name, age, gender, telephone no, e-mail address of a
   representative of a group. (If no e-mail address is available,
   please send a postcard for a reply with your address and name and a
   50-yen stamp on the front side). Send your message (and a reply
   postcard, if necessary) to the following address.

   JAXA ISAS "AKATSUKI" Campaign Office
   3-1-1 Yoshinodai, Sagamihara-shi, Kanagawa 229-8510

 - We will e-mail you (or send a reply postcard back in the case you
   send it to us) to let you know that we will have received your
   message.
 - We will not send you back your message. Your message and
   illustration may be used on our Web site, leaflet, and/or
   magazines for the purpose of public affairs and promotion. (Please
   refrain from sending any information, messages and/or illustrations
   that you do not want us to publish, such as personal information.)
   Copyright of the messages and illustrations basically belong to
   JAXA.
 - Please be aware that messages will be scaled down by a large
   percentage when they are printed on an aluminum plate.
 - JAXA (ISAS) will be in charge of accepting names and messages,
   counting them, and protecting your private information.

For inquiries about this campaign
 JAXA "AKATSUKI" Campaign Office
 Tel. 042-759-8646 (or +81-42-759-8646)

Reference
http://www.jaxa.jp/press/2009/10/20091023_akatsuki_campaign_e.html#at

This page URL:
http://www.jaxa.jp/press/2009/10/20091023_akatsuki_campaign_e.html

[yoichi]

December 4, 2009 Updated

Solar sail "IKAROS x Light Sail" Support Campaign
-- Let's set sail for the solar system by a solar yacht! --

A yacht travels through the ocean by wind pressure, then, theoretically, solar sails should move their way in space by receiving pressure of solar lights. JAXA and the Planetary Society of the U.S. will launch "IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun)" and "Light Sail-1" respectively in Japan Fiscal Year 2010 to carry out the verification tests of this technology. Taking this opportunity, the two organizations would like to hold a message campaign together to ask your support for the two missions.
If we can verify that solar sails move forward by solar lights, it will be a new propulsion technology that can save engine power and fuel consumption. For the successful verification, we would like to ask your support. Your messages will be attached to the IKAROS and Light Sail-1 to travel around space. We can accept your message till March 14, 2010 (Japan Standard Time.)

Campaign Site : http://www.jspec.jaxa.jp/ikaros_cam/e/index.html
Small Solar Power Sail Demonstrator (IKAROS)  : http://www.jspec.jaxa.jp/e/activity/ikaros.html

[woods170]

The Cassini spacecraft also visited Venus.

And so did the Galileo spacecraft before it went off to a double fly-by of Earth and finally off to Jupiter.

[DiggyCoxwell]

The PLANET-C is supposed to be launched at the beginning on 2010 and will be the first mission to Venus in almost 20 years. 

Um, I know it may look like the mission doesn't even exist judging by the lack of press releases, but aren't you forgetting ESA's Venus Express?

Sorry! My bad! I had the Magellan probe in mind.

No problemo. 

From the diagram, it appears Planet-C will take the low-energy
(Hohmann Transfer Orbit) path to Venus, arriving in Dec,12, 2010.
A simple calculation then shows that it would take 150 days, give or
take a week, to go from Earth to Venus.
Launch would then take place in July, 2010.

[ugordan]

The Cassini spacecraft also visited Venus.

However, it performed next to no scientific observations due to IIRC solar thermal constraints and no budget allocated for science planning. Only some calibration measurements were taken.

[jacqmans]

----------------------------------------------------------------------
                       ***  JAXA MAIL SERVICE  ***
                   Japan Aerospace Exploration Agency
----------------------------------------------------------------------
Interplanetary Kite-craft Accelerated by Radiation of the Sun (IKAROS)
         International Message Campaign for Mission Support

                                                December 4, 2009 (JST)
                             Japan Aerospace Exploration Agency (JAXA)

The Japan Aerospace Exploration Agency (JAXA) is scheduled to launch
the Interplanetary Kite-craft Accelerated by Radiation Of the Sun
(IKAROS)*1 by the H-IIA Launch Vehicle in Japan Fiscal Year 2010 (as a
secondary payload to the main payload, Venus Climate Orbiter
"AKATSUKI.")
We would like to launch a mission support campaign together with The
Planetary Society in the United States, which also plans to launch a
solar sail spacecraft named "LightSail-1"*2 at the end of 2010.
JAXA would like to encourage people all over the world to send us
their supportive messages to be carried aboard the IKAROS and the
LightSail-1 on printed aluminum plates or on a Mini-DVD. We sincerely
hope that our campaign will accelerate this international
collaboration, exchange and promote the public's understanding of
solar sail research and development.

The following is the information about the campaign.

1. Campaign name
   "Let's Set Sail for the Solar System on a Solar Yacht!"

2. Campaign period
   December 4 (Fri.), 2009 through March 14 (Sun.),
   2010 (Japan Standard Time) for the Mini-DVD,
   December 4 (Fri.), 2009 through February 28 (Sun.),
   2010 (Japan Standard Time) for printed metal plates.

3. How to apply
   Please send messages through the following websites.
     English site: http://www.jspec.jaxa.jp/e/index.html
     Japanese site: http://www.jspec.jaxa.jp/index.html

Your names and messages will be recorded and printed.
We are looking forward to hearing from many of you.


*1 IKAROS is a spacecraft that cruises by reflecting sunlight on its
   deployed membrane. While gaining propulsive force from sunlight,
   IKAROS also generates electric power from the thin film solar cells
   spanned on its membrane. IKAROS will be the first spacecraft in the
   world to demonstrate solar photon sail technology in interplanetary
   space and generate electric power from the thin film solar cells
   aboard.

*2 The Planetary Society is one of the world's leading organizations
   to promote planetary missions and exploration through flight
   projects, public relations, and educational activities. The
   LightSail-1 is a kite-shape spacecraft with a 5.5m x 5.5m square
   sail to reflect sunlight on an earth-revolving orbit at an altitude
   of 800 km. It will demonstrate that sunlight can provide propulsive
   power to spacecraft.

For more details about IKAROS, please check the following site.
http://www.jspec.jaxa.jp/e/activity/ikaros.html


This page URL:
http://www.jaxa.jp/press/2009/12/20091204_ikaros_e.html

[TheFallen]

The Planetary Society is now collecting names for the Akatsuki mission as well...complete with a certificate that looks much better than the one the JAXA site provides.

http://www.planetary.org/special/fromearth/akatsuki

[Robotbeat]

...

Looking forward to finally seeing a working solar sail

Nice video. What I'm most interested in is the thin-film solar array on the solar sail. The website says they are 25 microns thick. Including the 7 micron substrate and, say, 3 microns of slush, for 35 microns and assuming a density the same as silicon (substrate density is probably more like 1kg/liter) which is 2.33kg/l, and 10% efficient thin-film cells near Earth orbit, this should have a specific power greater than 1000W/kg, or greater specific power than any other deployed array by about a factor of 10. (That would be neglecting the wires and the weights on the ends of the sail and assuming the whole thing was covered with solar cells.) Clearly, this is an extremely light-weight deployment method for solar cells! A similar solar sail with a length of 100m (about the size of the ISS) could produce over a megawatt, yet weigh only a ton. Obviously, though, you are trading low mass for low stiffness, here, which presents difficulties, but you get a heck of a lot of power for your mass (plus, thin-film is usually cheaper than triple-junction). It will be interesting to see what kind of delta-v the hybrid propulsion follow-on will be capable of over its mission (hybrid solar sail and ion propulsion).

Also, the Very-Long-Baseline-Interferometry (VLBI) is neat.

[Robson68]

Really excited about Jaxa's work off late, they seem to be very forward thinking.

Just out of interest, is anyone aware of how much power is expected from the sail?

[DiggyCoxwell]

Really excited about Jaxa's work off late, they seem to be very forward thinking.

Just out of interest, is anyone aware of how much power is expected from the sail?

   If you have a reasonable math skills then try this equation to help yourself get the answer:

   a = 2Isr/cm

a = acceleration
I = solar radiation intensity (watts/meter squared) i.e.  1400 W/m^2
s = surface area of sail
r = reflection efficiency
m = mass
c = speed of light

[Robotbeat]

Really excited about Jaxa's work off late, they seem to be very forward thinking.

Just out of interest, is anyone aware of how much power is expected from the sail?

   If you have a reasonable math skills then try this equation to help yourself get the answer:

   a = 2Isr/m

a = acceleration
I = solar radiation intensity (watts/meter squared) i.e.  1400 W/m^2
s = surface area of sail
r = reflection efficiency
m = mass

I believe he's talking about electrical power. The sail is going to only be partially covered in solar panels (just a tiny fraction of the total sail's area), it's going to be closer to the Sun than the Earth is (if it's near Venus, that means the 1370W/m^2 is doubled), and will use thin-film solar cells, which are usually only 10% efficient at best.

It will be hard to guess how much power is to be expected, since the insolation is unknown, the surface area of the solar arrays is unknown, and the efficiency of the cells is unknown. Unknown to us, that is. We can make educated guesses at these quantities, but that's about it, unless someone fills us in.

[DiggyCoxwell]

Really excited about Jaxa's work off late, they seem to be very forward thinking.

Just out of interest, is anyone aware of how much power is expected from the sail?

   If you have a reasonable math skills then try this equation to help yourself get the answer:

   a = 2Isr/cm

a = acceleration
I = solar radiation intensity (watts/meter squared) i.e.  1400 W/m^2
s = surface area of sail
r = reflection efficiency
m = mass
c = speed of light

I believe he's talking about electrical power. The sail is going to only be partially covered in solar panels (just a tiny fraction of the total sail's area), it's going to be closer to the Sun than the Earth is (if it's near Venus, that means the 1370W/m^2 is doubled), and will use thin-film solar cells, which are usually only 10% efficient at best.

It will be hard to guess how much power is to be expected, since the insolation is unknown, the surface area of the solar arrays is unknown, and the efficiency of the cells is unknown. Unknown to us, that is. We can make educated guesses at these quantities, but that's about it, unless someone fills us in.

We'll have to get Robson68 to reply to know for sure.

But here's an example of how small the acceleration of a hypothetical solar sail will be:

but if m = 100kg.
        I = 2700 W/m^2 (near Venus)
        s =100 m^2
        r = 0.9

      a = (2)2700(0.9)(100) / 3.0 x 10^8 (100)

  The acceleration is tiny. It would take you a week to accelerate to a DeltaV of about 10m/s (jogging speed)