Friday is a good day to explore Mars. It’s air conditioned. At least, it’s that way during Mars Day at the Air and Space Museum. Otherwise, stay hydrated this weekend, especially if you’re attending any of the Civil War anniversary events in Manassas, or participating in the Saturday night race in Crystal City, or attending the Asian Festival at George Mason University.

The Capital Weather Gang says the weekend will be a blast, but not in a good way. Expect high heat each day.

Manassas anniversary

Post Now, our breaking news blog, reports that because of the heat, the National Park Service has canceled part of Friday’s program commemorating the 150th anniversary of the Civil War battle. Outdoor events scheduled for 2 p.m. to 6 p.m. at the National Battlefield Park have been called off, but museums, exhibits and the visitor center will remain open.

Expect extra traffic in and around Manassas this weekend during various anniversary events. Focal points are the battlefield park, Old Town Manassas and the Pageland Farm, just west of the battlefield park. Planners say the reenactments Saturday and Sunday at the farm are likely to draw more than 10,000 people.

Parking for those events will be on the grounds of the Jiffy Lube Live pavilion, 7800 Cellar Door Dr., Bristow. Visitors to events in Old Town Manassas can park at the Prince William County Fairgrounds, 10624 Dumfries Rd., Manassas. At the battlefield park, north of Interstate 66, there’s a large parking area on Chinn Ridge off Sudley Road (Route 234). Many of the anniversary events involve fees.

Some activities span the entire weekend. Here are a few highlights.

Friday: The focus today is on Old Town Manassas and the battlefield park. A parade of Civil War reenactors is scheduled for 10 a.m. to noon in Old Town Manassas. From 10 a.m. to 8 p.m., people will be visiting Camp Manassas, a 26-acre living history encampment at the Jennie Dean Historic Site, 9601 Wellington Rd., Manassas. (The camp is open Thursday through Sunday.)

Saturday/Sunday: The battle reenactment at Pageland Farm is scheduled for both days this weekend. Jiffy Lube Live opens for parking at 6 a.m. Take the shuttle buses to the reenactment site, which opens at 6:30 a.m.

The reenactment begins at 9:30 a.m., and sponsors recommend arriving before 9 a.m. Combat is scheduled to end at noon, and the site will close to the public at 2 p.m. The shuttle service ends at 3 p.m. See a pdf map and schedule.

Crystal City Twilighter 5K run

The run starts at 8:30 p.m. Saturday. Runners will follow a route that’s south of I-395 and between Route 1 and the George Washington Parkway.. See a map of the course.

Pre-race water: Chilled water will be available in the courtyard area of the finish festival.

These lane closings are scheduled for 6 p.m. to 10:45 p.m.

— Crystal Drive between 23rd Street and 20th Street. A single lane will be available to the entrance of the parking garage at 2100 Crystal Dr. An exit lane will be provided at 2200 Crystal Drive with access to 23rd Street.

— The horseshoe driveway at 2121 Crystal Drive.

These lane closures will be in effect between 7:30 to 9:15 p.m.

— Crystal Drive between Route 1 and 15th Street.

— Two north bound lanes between 15th and 12th streets. The western-most northbound lane will remain open for garage access. Access to 12th Street will be available via 200 12th Street Driveway.

— One southbound lane of Crystal Drive between 15th Street and 20th Street. The western-most southbound lane between 15th and 20th Street will remain open to provide garage parking access.

— Westbound lanes of 12th Street between Crystal Drive and South Eads Street.

— Traffic along the eastbound lane of 12th Street will be reversed to westbound traffic only. Northbound traffic will be diverted into the driveway at 1200 Crystal Drive to continue westbound on 12th Street.

— Potomac Avenue between Crystal Drive and 33rd Street.

— 33rd Street between Potomac Avenue and Crystal Drive.

Metro weekend delays

Just like last weekend, the major project is on the Orange Line, where rail service will be suspended between East Falls Church and West Falls Church.

Orange Line: From 10 p.m. Friday through the midnight closing Sunday, free shuttle buses will replace trains between East Falls Church and West Falls Church stations to allow for construction that will eventually connect the new Dulles rail line to the rest of the Metrorail system. The stations will remain open.

The last train will leave Vienna 20 minutes earlier than usual, at 2:08 a.m. Friday and Saturday nights and at 11:08 p.m. on Sunday. Between Vienna and West Falls Church, trains will operate every 24 minutes and share one track while workers replace cross ties and insulators.

Riders traveling through the work zone should allow about half an hour of extra travel time.

Red Line: From 10 p.m. Friday through Sunday’s closing, trains will share a track between Dupont Circle and Judiciary Square. Workers will be repairing the ceiling at Farragut North, as well as replacing rail fasteners and installing new emergency phones and communication cables.

At Farragut North, the north entrance (L Street/Connecticut Avenue NW) will be closed from 10 p.m. Friday through the end of service Sunday for repairs in the station. Use the entrance at K Street and Connecticut Avenue.

Trains will operate every 20 minutes between Dupont Circle and Judiciary Square. Between 9:30 a.m. and 9 p.m. Saturday and Sunday, trains will leave the ends of the line at Glenmont and Shady Grove about every 10 minutes. Every other train from Shady Grove will terminate at Dupont Circle and head back. Every other train leaving Glenmont will terminate at Union Station and head back.

At all other times during the weekend, trains will leave the ends of the line every 20 minutes. They will be subject to delays en route because of the single tracking, and riders should add about half an hour to normal travel times.

The last train from Glenmont will leave 11 minutes earlier than usual, at 2:26 a.m. on Friday and Saturday nights and at 11:26 p.m. on Sunday.

Green Line: From 10 p.m. Friday through Sunday’s closing, trains will share a track between Navy Yard and Anacostia. Workers will be rehabilitating the tracks. Metro doesn’t expect this will cause delays.

Beltway/Telegraph Road

From 9 p.m. Friday to 5 a.m. Monday, the left lane of the Capital Beltway’s outer loop (I-95/495 North) will be closed between the Eisenhower Connector and Telegraph Road for paving. Two lanes will remain open, but the Wilson Bridge project, which is doing the work, expects significant traffic delays.

Constitution Avenue

From 7 a.m. to 5 p.m. this Saturday and next, expect to find up to three lanes closed in each direction on Constitution Avenue between 23rd and 17th streets for the National Park Service reconstruction project.From 5:30 a.m. to 3:30 p.m. Monday through Friday, expect to find up to two lanes closed in each direction.

New Hampshire Avenue

Two southbound lanes have shifted about 12 feet to the right, placing the traffic on the permanent alignment crossing the Intercounty Connector. Pedestrian access will be maintained on new sidewalk along southbound New Hampshire.

On July 30, workers will shift the northbound lanes about 24 feet to the left to allow traffic over the newly constructed section of the New Hampshire Avenue bridge above the connector. The northbound shift will start north of Copley Lane.

Route 29/Fairland Road

Drivers heading south on Route 29 in Montgomery County will need to look sharp to catch the new exit for left turns onto Fairland Road. The Maryland State Highway Administration built the new ramp as part of the Intercounty Connector project, which will have an interchange with Route 29 in the Fairland area.

The ramp already is used by southbound drivers who want to make a right turn on Fairland Road and head west. As of this week, the ramp also will be used by southbound drivers who want to turn left and head east. Those drivers have been going up to the light at the Fairland intersection to make the left.

So drivers heading east now will have to remember to look for this right-hand ramp, which starts about a third of a mile before the intersection.

Clara Barton Parkway

D.C. Water continues to work on an odor abatement facility along the Clara Barton Parkway about three miles west of Chain Bridge. Watch for construction vehicles entering and exiting the parkway at the construction site, adjacent to the Little Falls pumping station. This work is scheduled to continue until spring 2012.

Anacostia Freeway

The District Department of Transportation is repairing the bridge over the Anacostia Park Entrance on the Anacostia Freeway (DC-295).Work is scheduled to continue through Sept. 20. The work hours are 7 a.m. to 4 p.m. and 8 p.m. to 5 a.m. Single lanes will be closed.

Route 29/Gallows Road

The Virginia Department of Transportation says it’s ready to start rebuilding the congested intersection at Route 29 and Gallows Road in Merrifield. The project is scheduled to be done by the end of 2012.

During construction, night-time drivers will at times be funneled down to a single lane through the work zone. One section of Gallows Road just north of the intersection will be reduced to one lane in each direction for about four months. VDOT says it will announce a schedule for the lane closings.

A community meeting to discuss the project with VDOT officials is scheduled for 7 p.m. to 9 p.m. Wednesday at Luther Jackson Middle School, 3020 Gallows Road in Falls Church. A brief presentation will begin at 7:30, followed by a question-and-answer period.

Beltway/Kenilworth Avenue

Drivers will find up to three lanes closed on the Capital Beltway’s inner loop (I-95/I-495 South) Sunday through Thursday nights at the Kenilworth Avenue bridge, which is undergoing a rehabilitation scheduled to be done by fall.

The phased-in lane closings will start with a single right lane closing at 8 p.m. and progress to a three-lane closure by 10 p.m. One lane will remain open to traffic.

The overnight lane closures will last several weeks while the concrete deck is removed. All lanes will reopen by 5 o’clock each morning.

Beltway/Silver Spring

Beltway commuters in Maryland should prepare to encounter a new work zone between Route 29 and Seminary Road in Silver Spring, where the state is about to start a resurfacing project scheduled to be done by Thanksgiving.

Lane closings are scheduled to begin Saturday, July 30. But before that, drivers should watch for preparatory work, including the placement of project equipment and installation of temporary signs.

17th Street NW

The National Park Service has reduced the number of travel lanes on 17th Street from four to two, with one lane open in each direction.

Two-way traffic is and will be maintained at all times during this first phase of the levee construction project. Work on the levee itself will progress from the middle of 17th Street east toward the Washington Monument.

When the levee work is completed on the east side of 17th Street (the side closest to the Washington Monument), work will then move to the west side of 17th Street. The project is scheduled to be done late this year.